Organelle Transport Research Articles

Autophagy in the nervous system: general principles and specific functions

Autophagy is an intracellular mechanism for the isolation, transport and degradation of macromolecules and organelles. The physiological significance of autophagy lies, firstly, in maintaining the constancy of the intracellular environment through the timely disposal of proteins with a disrupted structure and damaged organelles. Secondly, due to the selective degradation of macromolecules, autophagy supplies the cell with monomers, which are then used by it to synthesize new compounds, which serves to ensure the rearrangement of cellular metabolism in the processes of cell differentiation, ontogenesis and adaptation to environmental challenges. Autophagy is an extremely important mechanism for maintaining normal functioning of postmitotic and differentiated cells, including neurons. Impaired neuronal autophagy leads to the formation of aggregated protein plaques, the accumulation of damaged cellular organelles, defects in the structure of processes and neuronal degeneration, which often accompanies to the progression of some forms of neurodegenerative diseases. In addition, the role of autophagy in synaptic plasticity and memory mechanisms has been established. Since autophagy has a significant impact on cellular metabolism, the study of the regulation and main pathways of this mechanism may be crucial in the elaboration of means and approaches to the treatment and prevention of many pathologies that progress with age. This review describes the basic concepts of the autophagy process, summarizes the key functions of autophagy in cells, and also presents current data on its role in ensuring the normal metabolism and implementation of specific functions of neurons.

Transcriptional Profiling of Tofacitinib Treatment in Juvenile Idiopathic Arthritis: Implications for Treatment Response Prediction.

To assess changes in gene expression following tofacitinib treatment and investigate transcription patterns as potential predictors of treatment response in patients with active juvenile idiopathic arthritis (JIA). Whole blood samples were collected from JIA patients at baseline and after 18 weeks of open-label tofacitinib treatment (clinical trial NCT02592434). Patients who achieved a JIA-American College of Rheumatology (ACR) response of 70 or above at week 18 were classified as treatment-responders (TR) while those with at most a JIA-ACR30 response were classified as poor-responders (PR). Differential gene expression and gene ontology (GO) over-representation analyses were performed to compare RNA expression between week 18 and baseline samples, as well as between PR and TR samples at baseline. Samples from 67 patients at baseline and 60 at week 18 were analyzed. Following 18 weeks of tofacitinib treatment across all JIA subjects, 883 genes showed significant differential expression (week 18 - baseline). The most strongly downregulated genes were over-represented within IL-7, type I, and type II interferon pathways, while upregulated genes were enriched in ontologies related to neuronal cell processes and cell signaling. Comparing PR and TR at baseline, 663 genes showed differential expression. Upregulated genes were over-represented within ontologies including activation of MAPK activity (p=9.40x10-5), myeloid cell development (p=8.13 x10-5), activation of GTPase activity (p=0.00015), and organelle transport along microtubules (p=0.00021). Tofacitinib treatment in JIA downregulated genes in interferon and IL-7 signaling pathways regardless of effectiveness. Furthermore, baseline upregulation of MAPK signaling may predict poor response to tofacitinib treatment in JIA.

Understanding the molecular regulatory mechanisms of autophagy in lung disease pathogenesis.

Lung disease development involves multiple cellular processes, including inflammation, cell death, and proliferation. Research increasingly indicates that autophagy and its regulatory proteins can influence inflammation, programmed cell death, cell proliferation, and innate immune responses. Autophagy plays a vital role in the maintenance of homeostasis and the adaptation of eukaryotic cells to stress by enabling the chelation, transport, and degradation of subcellular components, including proteins and organelles. This process is essential for sustaining cellular balance and ensuring the health of the mitochondrial population. Recent studies have begun to explore the connection between autophagy and the development of different lung diseases. This article reviews the latest findings on the molecular regulatory mechanisms of autophagy in lung diseases, with an emphasis on potential targeted therapies for autophagy.

Molecular Motors in Myelination and Their Misregulation in Disease.

Molecular motors are cellular components involved in the intracellular transport of organelles and materials to ensure cell homeostasis. This is particularly relevant in neurons, where the synaptic components synthesized in the soma need to travel overlong distances to their destination. They can walk on microtubules (kinesins and dyneins) or actin filaments (myosins), themajor components of cell cytoskeleton. While kinesins mostly perform the anterograde transport of intracellular components toward the plus ends of microtubules located distally in cell processes, cytoplasmic dyneins allow the retrograde flux of intracellular cargo toward the minus ends of microtubules located at the cell soma. Axon myelination represents a major aspect of neuronal maturation and is essential for neuronal function, as it speeds up the transmission of electrical signals. Increasing evidence supports a role for molecular motors in the homeostatic control of myelination. This role includes the trafficking of myelin components along the processes of myelinating cells and local regulation of pathways that ensure axon wrapping. Dysfunctional control of the intracellular transport machinery has thereforebeen linked to several brain pathologies, including demyelinating diseases. These disordersinclude a broad spectrum of conditions characterized by pathological demyelination of axons within the nervous system, ultimately leading to axonal degeneration and neuronal death, withmultiple sclerosis representing the most prevalent and studied condition. This review highlights the involvement of molecular motors in the homeostatic control of myelination. It also discusses studies that have yielded insights into the dysfunctional activity of molecular motors in the pathophysiology of multiple sclerosis.

Biogenesis and reformation of synaptic vesicles.

Communication within the nervous system relies on the calcium-triggered release of neurotransmitter molecules by exocytosis of synaptic vesicles (SVs) at defined active zone release sites. While decades of research have provided detailed insight into the molecular machinery for SV fusion, much less is known about the mechanisms that form functional SVs during the development of synapses and that control local SV reformation following exocytosis in the mature nervous system. Here we review the current state of knowledge in the field, focusing on the pathways implicated in the formation and axonal transport of SV precursor organelles and the mechanisms involved in the local reformation of SVs within nerve terminals in mature neurons. We discuss open questions and outline perspectives for future research.

Spatiotemporal regulation of organelle transport by spindle position checkpoint kinase Kin4.

Asymmetric cell division in Saccharomyces cerevisiae involves Class V myosin-dependent transport of organelles along the polarised actin cytoskeleton to the emerging bud. Vac17 is the vacuole/lysosome-specific myosin receptor. Its timely breakdown terminates transport and results in the proper positioning of vacuoles in the bud. Vac17 breakdown is controlled by the bud-concentrated p21-activated kinase, Cla4, and the E3-Ubiquitin ligase, Dma1. We found that the spindle position checkpoint kinase, Kin4, and to a lesser extent its paralog Frk1, contribute to successful vacuole transport by preventing the premature breakdown of Vac17 by Cla4 and Dma1. Furthermore, Kin4 and Cla4 contribute to the regulation of peroxisome transport. We conclude that Kin4 acts antagonistically to the Cla4-/Dma1-pathway to coordinate spatiotemporal regulation of organelle transport.

The Ovary Structure in Terrestrial Parasitengona Mites: The Case of Trombidiidae (Acariformes: Parasitengona).

Species of mites (Chelicerata: Arachnida) show a great variety of structures of the female gonads. In both evolutionary lines, Acariformes and Parasitiformes, the panoistic ovary, in which all germline cysts differentiate into oocytes, and the meroistic ovary, in which the oocytes grow supported by the nurse cells, have been documented. A less pronounced variation in the gonad structure could be expected at lower systematic levels, hence, we ask about the degree of differences within the family that is subordinate to Acariformes and represents the cohort Parasitengona. Based on the members of Trombidiidae (Acariformes: Trombidiformes, Parasitengona, Trombidioidea), we test the hypothesis that the general ovary type is constant at the family level. Our previous research on the female gonad in Allothrombium fuliginosum revealed that the meroistic ovary occurs in these mites. Here, we proceed with a detailed insight into the ovary structure in A. fuliginosum and examine the structure of the female gonad in other members of Trombidiidae, focusing on the following representatives of its nominotypical genus Trombidium: Trombidium brevimanum, Trombidium holosericeum, Trombidium heterotrichum, and Trombidium latum. For all species, studied with light, fluorescence, and transmission electron microscopy, we could confirm the presence of the meroistic ovary that is highly similar with respect to general architecture. The germline cysts show similarities in general morphology and the mode of germline cell differentiation; they consist of a few nurse cells and one oocyte. The connection between the nurse cells and oocytes is maintained by trophic cords that serve for the transport of organelles and macromolecules. Our results confirm the constancy of the structure of the female gonad at the intrageneric level and provide further support for the hypothesis on the lack of differences at the intrafamily level.

Myosin superfamily members during myelin formation and regeneration.

Myelin is an insulator that forms around axons that enhance the conduction velocity of nerve fibers. Oligodendrocytes dramatically change cell morphology to produce myelin throughout the central nervous system (CNS). Cytoskeletal alterations are critical for the morphogenesis of oligodendrocytes, and actin is involved in cell differentiation and myelin wrapping via polymerization and depolymerization, respectively. Various protein members of the myosin superfamily are known to be major binding partners of actin filaments and have been intensively researched because of their involvement in various cellular functions, including differentiation, cell movement, membrane trafficking, organelle transport, signal transduction, and morphogenesis. Some members of the myosin superfamily have been found to play important roles in the differentiation of oligodendrocytes and in CNS myelination. Interestingly, each member of the myosin superfamily expressed in oligodendrocyte lineage cells also shows specific spatial and temporal expression patterns and different distributions. In this review, we summarize previous findings related to the myosin superfamily and discuss how these molecules contribute to myelin formation and regeneration by oligodendrocytes.

Totally asymmetric simple exclusion process on a dynamic lattice with local inhomogeneity

In this manuscript, we introduce a totally asymmetric simple exclusion process on a dynamic lattice with inhomogeneity to model motor-based long-range transport along microtubules (MTs) which exhibit cycles of growth, shortening and regrowth at their growing tips. By mean-field approximation and numerical simulations, we explore phase diagrams for the particle density near the dynamic end of the lattice as well as over the entire lattice. In particular, we find seven different phases for the density over the entire lattice and explore the corresponding phase diagram by analytical analysis. Interestingly, we find that the density may have a linear profile in part of the lattice. When the lattice has a defect, we separate the lattice into two subsystems: a right subsystem with fixed length and a defect in the middle and a left subsystem with dynamic length. When the right subsystem is in maximum-current phase, we calculate an analytical approximation of the density away from the boundaries and the defect site and the density is in association with the reduced hopping rate at the defect site; the density at the left side of the defect site serves as the effective entry rate of the left subsystem. We find that with defects, the linear profiles no longer appear at the left end of the left subsystem and only five possible phases could occur. This is a step-forward to a more comprehensive mathematical description of intracellular long-range transport of organelles along MTs with instability.

Role of 14-3-3 protein family in the pathobiology of EBV in immortalized B cells and Alzheimer's disease.

Several studies have revealed that Epstein-Barr virus (EBV) infection raised the likelihood of developing Alzheimer's disease (AD) via infecting B lymphocytes. The purpose of the current investigation was to assess the possible association between EBV infection and AD. The microarray datasets GSE49628, GSE126379, GSE122063, and GSE132903 were utilized to extract DEGs by using the GEO2R tool of the GEO platform. The STRING tool was used to determine the interaction between the DEGs, and Cytoscape was used to visualize the results. The DEGs that were found underwent function analysis, including pathway and GO, using the DAVID 2021 and ClueGo/CluePedia. By using MNC, MCC, Degree, and Radiality of cytoHubba, we identified seven common key genes. Gene co-expression analysis was performed through the GeneMANIA web tool. Furthermore, expression analysis of key genes was performed through GTEx software, which have been identified in various human brain regions. The miRNA-gene interaction was performed through the miRNet v 2.0 tool. DsigDB on the Enrichr platform was utilized to extract therapeutic drugs connected to key genes. In GEO2R analysis of datasets with |log2FC|≥ 0.5 and p-value <0.05, 8386, 10,434, 7408, and 759 genes were identified. A total of 141 common DEGs were identified by combining the extracted genes of different datasets. A total of 141 nodes and 207 edges were found during the PPI analysis. The DEG GO analysis with substantial alterations disclosed that they are associated to molecular functions and biological processes, such as positive regulation of neuron death, autophagy regulation of mitochondrion, response of cell to insulin stimulus, calcium signaling regulation, organelle transport along microtubules, protein kinase activity, and phosphoserine binding. Kyoto Encyclopedia of Genes and Genomes analysis discovered the correlation between the DEGs in pathways of neurodegeneration: multiple disease, cell cycle, and cGMP-PKG signaling pathway. Finally, YWHAH, YWHAG, YWHAB, YWHAZ, MAP2K1, PPP2CA, and TUBB genes were identified that are strongly linked to EBV and AD. Three miRNAs, i.e., hsa-mir-15a-5p, hsa-let-7a-5p, and hsa-mir-7-5p, were identified to regulate most of hub genes that are associated with EBV and AD. Further top 10 significant therapeutic drugs were predicted. We have discovered new biomarkers and therapeutic targets for AD, as well as the possible biological mechanisms whereby infection with EBV may be involved in AD susceptibility for the first time.

Actomyosin organelle functions of SPIRE actin nucleators precede animal evolution

An important question in cell biology is how cytoskeletal proteins evolved and drove the development of novel structures and functions. Here we address the origin of SPIRE actin nucleators. Mammalian SPIREs work with RAB GTPases, formin (FMN)-subgroup actin assembly proteins and class-5 myosin (MYO5) motors to transport organelles along actin filaments towards the cell membrane. However, the origin and extent of functional conservation of SPIRE among species is unknown. Our sequence searches show that SPIRE exist throughout holozoans (animals and their closest single-celled relatives), but not other eukaryotes. SPIRE from unicellular holozoans (choanoflagellate), interacts with RAB, FMN and MYO5 proteins, nucleates actin filaments and complements mammalian SPIRE function in organelle transport. Meanwhile SPIRE and MYO5 proteins colocalise to organelles in Salpingoeca rosetta choanoflagellates. Based on these observations we propose that SPIRE originated in unicellular ancestors of animals providing an actin-myosin driven exocytic transport mechanism that may have contributed to the evolution of complex multicellular animals.

PKA Activity-Driven Modulation of Bidirectional Long-Distance transport of Lysosomal vesicles During Synapse Maintenance.

The bidirectional long-distance transport of organelles is crucial for cell body-synapse communication. However, the mechanisms by which this transport is modulated for synapse formation, maintenance, and plasticity are not fully understood. Here, we demonstrate through quantitative analyses that maintaining sensory neuron-motor neuron synapses in the Aplysia gill-siphon withdrawal reflex is linked to a sustained reduction in the retrograde transport of lysosomal vesicles in sensory neurons. Interestingly, while mitochondrial transport in the anterograde direction increases within 12 hours of synapse formation, the reduction in lysosomal vesicle retrograde transport appears three days after synapse formation. Moreover, we find that formation of new synapses during learning induced by neuromodulatory neurotransmitter serotonin further reduces lysosomal vesicle transport within 24 hours, whereas mitochondrial transport increases in the anterograde direction within one hour of exposure. Pharmacological inhibition of several signaling pathways pinpoints PKA as a key regulator of retrograde transport of lysosomal vesicles during synapse maintenance. These results demonstrate that synapse formation leads to organelle-specific and direction specific enduring changes in long-distance transport, offering insights into the mechanisms underlying synapse maintenance and plasticity.

Expanding science skills: teaching tissue culture, data analysis, and reporting through imaging the actin cytoskeleton.

Within the eukaryotic cell, the actin cytoskeleton is a crucial structural framework that maintains cellular form, regulates cell movement and division, and facilitates the internal transportation of proteins and organelles. External cues induce alterations in the actin cytoskeleton primarily through the activation of Rho GTPases, which then bind to a diverse array of effector proteins to promote the local assembly or disassembly of actin. We have harnessed the extensively studied functions of RhoA in the dynamics of the actin cytoskeleton to craft a practical series for Stage 2 Biology students. This series not only imparts essential tissue culture laboratory skills but also reinforces them through repetition. These activities are presented in a scenario designed for students to explore the function of a hypothetical RhoA family member. Students produce slides from transfected cells, undertake fluorescence microscopy, process the images using ImageJ, and compile their findings in a comprehensive scientific report. The composition of the report requires independent acquisition of new knowledge and synoptic learning. According to student feedback, this early experience greatly aids in solidifying and honing the skills required to report on more extensive and intricate research projects, such as capstone projects.

The interaction of ER stress and autophagy in trophoblasts: navigating pregnancy outcome†.

The endoplasmic reticulum is a complex and dynamic organelle that initiates unfolded protein response and endoplasmic reticulum stress in response to the accumulation of unfolded or misfolded proteins within its lumen. Autophagy is a paramount intracellular degradation system that facilitates the transportation of proteins, cytoplasmic components, and organelles to lysosomes for degradation and recycling. Preeclampsia and intrauterine growth retardation are two common complications of pregnancy associated with abnormal trophoblast differentiation and placental dysfunctions and have a major impact on fetal development and maternal health. The intricate interplay between endoplasmic reticulum stress, and autophagy and their impact on pregnancy outcomes, through mediating trophoblast differentiation and placental development, has been highlighted in various reports. Autophagy controls trophoblast regulation through a variety of gene expressions and signaling pathways while excessive endoplasmic reticulum stress triggers downstream apoptotic signaling, culminating in trophoblast apoptosis. This comprehensive review delves into the intricacies of placental development and explores the underlying mechanisms of preeclampsia and intrauterine growth retardation. In addition, this review will elucidate the molecular mechanisms of endoplasmic reticulum stress and autophagy, both individually and in their interplay, in mediating placental development and trophoblast differentiation, particularly highlighting their roles in preeclampsia and intrauterine growth retardation development. This research seeks to the interplay between endoplasmic reticulum stress and impaired autophagy in the placental trophoderm, offering novel insights into their contribution to pregnancy complications.

Myosin XI, a model of its conserved role in plant cell tip growth.

In eukaryotic cells, organelle and vesicle transport, positioning, and interactions play crucial roles in cytoplasmic organization and function. These processes are governed by intracellular trafficking mechanisms. At the core of that trafficking, the cytoskeleton and directional transport by motor proteins stand out as its key regulators. Plant cell tip growth is a well-studied example of cytoplasm organization by polarization. This polarization, essential for the cell's function, is driven by the cytoskeleton and its associated motors. This review will focus on myosin XI, a molecular motor critical for vesicle trafficking and polarized plant cell growth. We will center our discussion on recent data from the moss Physcomitrium patens and the liverwort Marchantia polymorpha. The biochemical properties and structure of myosin XI in various plant species are discussed, highlighting functional conservation across species. We further explore this conservation of myosin XI function in the process of vesicle transport in tip-growing cells. Existing evidence indicates that myosin XI actively organizes actin filaments in tip-growing cells by a mechanism based on vesicle clustering at their tips. A hypothetical model is presented to explain the essential function of myosin XI in polarized plant cell growth based on vesicle clustering at the tip. The review also provides insight into the in vivo localization and dynamics of myosin XI, emphasizing its role in cytosolic calcium regulation, which influences the polymerization of F-actin. Lastly, we touch upon the need for additional research to elucidate the regulation of myosin function.

Minimal Mechanisms of Microtubule Length Regulation in Living Cells.

The microtubule cytoskeleton is responsible for sustained, long-range intracellular transport of mRNAs, proteins, and organelles in neurons. Neuronal microtubules must be stable enough to ensure reliable transport, but they also undergo dynamic instability, as their plus and minus ends continuously switch between growth and shrinking. This process allows for continuous rebuilding of the cytoskeleton and for flexibility in injury settings. Motivated by in vivo experimental data on microtubule behavior in Drosophila neurons, we propose a mathematical model of dendritic microtubule dynamics, with a focus on understanding microtubule length, velocity, and state-duration distributions. We find that limitations on microtubule growth phases are needed for realistic dynamics, but the type of limiting mechanism leads to qualitatively different responses to plausible experimental perturbations. We therefore propose and investigate two minimally-complex length-limiting factors: limitation due to resource (tubulin) constraints and limitation due to catastrophe of large-length microtubules. We combine simulations of a detailed stochastic model with steady-state analysis of a mean-field ordinary differential equations model to map out qualitatively distinct parameter regimes. This provides a basis for predicting changes in microtubule dynamics, tubulin allocation, and the turnover rate of tubulin within microtubules in different experimental environments.

Miro GTPases at the Crossroads of Cytoskeletal Dynamics and Mitochondrial Trafficking.

Miro GTPases are key components in the machinery responsible for transporting mitochondria and peroxisomes along microtubules, and also play important roles in regulating calcium homeostasis and organizing contact sites between mitochondria and the endoplasmic reticulum. Moreover, Miro GTPases have been shown to interact with proteins that actively regulate cytoskeletal organization and dynamics, suggesting that these GTPases participate in organizing cytoskeletal functions and organelle transport. Derailed mitochondrial transport is associated with neuropathological conditions such as Parkinson's and Alzheimer's diseases. This review explores our recent understanding of the diverse roles of Miro GTPases under cytoskeletal control, both under normal conditions and during the course of human diseases such as neuropathological disorders.

Abstract 5723: Selectivity profiling of small molecule kinesin inhibitors using microplate-based ATPase activity assay

Abstract Kinesin superfamily proteins (KIFs) are a large family of molecular motor proteins, that share a highly conserved motor domain. KIFs play an important role in cell division and transport of vesicles and organelles within cells. Mitotic kinesins hydrolyze ATP through its ATPase activity to move along the spindle microtubules and carry out several functions during mitosis to facilitate precise chromosome segregation. Altered expressions of several kinesins are shown in various cancers, fueling the aggressive nature of cancers leading to genomic instability. KIF11/Eg5 overexpression is shown in various cancers including hepatic carcinoma, lung, prostate, colorectal, gastric, and pancreatic cancers. Small molecule inhibitors of KIF11/Eg5 and CENP-E are shown to result in mitotic arrest leading to apoptosis in tumor cell lines. Despite the poor clinical outcome of several Eg5 and CENP-E inhibitors entered in clinical trials, targeting kinesins remains an attractive anti-cancer therapeutic approach. Recently, an inhibitor of KIF18A has entered clinical trial for treatment of solid tumors with high chromosomal instability. Here we show development of a microplate based biochemical screening assays for a panel of kinesin motor domain proteins. We summarize kinetic characterization of kinesin proteins and study the selectivity of various previously reported KIF18A, Eg5, CENP-E inhibitors across a kinesin selectivity panel. Citation Format: Brenna P. Lee, Sung Won Oh, Kurumi Y. Horiuchi, Safnas F. AbdulSalam. Selectivity profiling of small molecule kinesin inhibitors using microplate-based ATPase activity assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5723.

MAPT Mutations V337M and N297K Alter Organelle Trafficking in Frontotemporal Dementia Patient-Specific Motor Neurons.

Frontotemporal dementia (FTD) is a neurodegenerative disease characterized by the progressive loss of neurons mainly in the frontal and temporal lobes of the brain. Mutations (e.g., V337M, N297K) in the microtubule-associated protein TAU (MAPT) are responsible 5-20% of familial FTD cases and have been associated with defects in organelle trafficking that plays a critical role in the proper function of cells, including transport of essential molecules and degradation of waste products. Due to the critical role of TAU mutations in microtubule stabilization and organelle transportation, it is of great interest to study these molecular mechanisms to develop effective therapeutic strategies. Therefore, herein, we analyzed mitochondrial and lysosomal trafficking in disease-specific spinal motor neurons by using live cell imaging in undirected (uncompartmentalized) and directed (compartmentalized) cell culture systems. While V337M neurons only expressed 3R TAU, the N297K mutant neurons expressed both 3R and 4R TAU. Axonal trafficking was affected differentially in V337M and N297 MAPT mutated neurons. These findings suggest that the MAPT mutations V337M and N297K impaired axon physiology differentially, which highlights the need for mutation- and/or 3R/4R TAU-specific therapeutic approaches.

E3 Ligases Regulate Organelle Inheritance in Yeast.

Saccharomyces cerevisiae proliferates by budding, which includes the formation of a cytoplasmic protrusion called the 'bud', into which DNA, RNA, proteins, organelles, and other materials are transported. The transport of organelles into the growing bud must be strictly regulated for the proper inheritance of organelles by daughter cells. In yeast, the RING-type E3 ubiquitin ligases, Dma1 and Dma2, are involved in the proper inheritance of mitochondria, vacuoles, and presumably peroxisomes. These organelles are transported along actin filaments toward the tip of the growing bud by the myosin motor protein, Myo2. During organelle transport, organelle-specific adaptor proteins, namely Mmr1, Vac17, and Inp2 for mitochondria, vacuoles, and peroxisomes, respectively, bridge the organelles and myosin. After reaching the bud, the adaptor proteins are ubiquitinated by the E3 ubiquitin ligases and degraded by the proteasome. Targeted degradation of the adaptor proteins is necessary to unload vacuoles, mitochondria, and peroxisomes from the actin-myosin machinery. Impairment of the ubiquitination of adaptor proteins results in the failure of organelle release from myosin, which, in turn, leads to abnormal dynamics, morphology, and function of the inherited organelles, indicating the significance of proper organelle unloading from myosin. Herein, we summarize the role and regulation of E3 ubiquitin ligases during organelle inheritance in yeast.