Focal Adhesion Sites Research Articles

Expression of C-Terminal Modified Serine Palmitoyltransferase-1 Alters Chemosensitivity of Inflammation-Associated Human Cancer Cell Lines

Background: The human serine palmitoyltransferase-1, SPTLC1, subunit is emerging as a stress responsive protein with putative role in modulating cellular stress response behavior. When compared to the parental cell line, recombinant Glioma cells expressing C-terminal modified SPTLC1 are found to show resistance to the cytotoxic effect of polycyclic hydrocarbons, PHs, including the environmental contaminant 3-methylcholanthrene. This novel functional association of SPTLC1 expression with proliferative capacity is thought to be due, in part, to its ability for crosstalk with protein regulators of different biological processes. Whether the effect of SPTLC1 on sensitivity to PHs extends to therapeutic drugs and the progression of the malignant phenotype is of research interest. Methods: In the current study, sub-cellular localization was by immunostaining for SPTLC1 in untreated and chemical treated cells and detection with confocal microscopy. The effect expressing C-terminal modified SPTLC1, in cancer cell lines of the inflammation-associated type, has on chemosensitivity and gene expression was also assessed. Parent Glioma LN18 and SKN-SH cells and their SPTLC1 recombinants were each treated with Glutamate, an excitatory neurotransmitter that can participate in both neuronal and excitotoxic signaling. In addition to the Glioma and SKN-SH cells, the PC3 prostate cancer and 647V bladder cancer cell lines were also treated with Celecoxib, a potent inhibitor of cyclooxygenase 2, COX-2, and an anti-inflammatory drug recently found to have anti-neoplastic activity against several malignancies. Results: Confocal microscopy revealed that Celecoxib mediates both rapid and enhanced redistribution of SPTLC1 and COX-2, to focal adhesion sites. In cell viability assay, SPTLC1 recombinant cells exhibited differential but dose-dependent resistance to excitotoxic levels of Glutamate. Drug co-treatment with a non-lethal dose of the potent kinase inhibitor, Sulfasalazine, increased the anti-proliferation effect of Celecoxib in a dose-dependent manner for all the cell lines tested. Conclusions: The effect of SPTLC1 expression on cellular chemosensitivity seen in the present study further highlights possible role of a C-terminal modified SPTLC1 variant in the biologic modulation of cellular behavior in response to therapeutic anticancer drugs.

Chemical Synthesis, Characterisation, and Biocompatibility of Nanometre Scale Porous Anodic Aluminium Oxide Membranes for Use as a Cell Culture Substrate for the Vero Cell Line: A Preliminary Study

In this preliminary study we investigate for the first time the biomedical potential of using porous anodic aluminium oxide (AAO) membranes as a cell substrate for culturing the Cercopithecus aethiops (African green monkey) Kidney (Vero) epithelial cell line. One advantage of using the inorganic AAO membrane is the presence of nanometre scale pore channels that allow the exchange of molecules and nutrients across the membrane. The size of the pore channels can be preselected by adjusting the controlling parameters of a temperature controlled two-step anodization process. The cellular interaction and response of the Vero cell line with an in-house synthesised AAO membrane, a commercially available membrane, and a glass control were assessed by investigating cell adhesion, morphology, and proliferation over a 72 h period. The number of viable cells proliferating over the respective membrane surfaces revealed that the locally produced in-house AAO membrane had cells numbers similar to the glass control. The study revealed evidence of focal adhesion sites over the surface of the nanoporous membranes and the penetration of cellular extensions into the pore structure as well. The outcome of the study has revealed that nanometre scale porous AAO membranes have the potential to become practical cell culture scaffold substrates with the capability to enhance adhesion and proliferation of Vero cells.

CagA, a Master Regulator of Host Protein Phosphorylation Events

loop regulating CagA phosphorylation status and activity [18]. The second mechanism of host protein dephosphorylation was defined by the ability of activated CagAp-Tyr to bind to the SH2domain of Shp-2 tyrosine phosphatase [19], which triggered the dephosphorylation of focal adhesion kinase (FAK)and as a consequence of FAK substrates like Paxillin [20]. In gastric epithelial cells reduced FAK activity leads to a reduction of focal adhesion sites and contributes to cell detachment and increased cell motility.

Abstract P5-07-09: An aberrant spliced transcript of focal adhesion kinase expressed in human breast cancer

Abstract Background: Focal adhesion kinase is a tyrosine kinase that plays a critical role at focal adhesion sites in cell mobility and migration. The over-expression and mutation of FAK, which promotes tumor cell invasion and survival, frequently occurs in tumors, allowing FAK to be recognized as a cancer-relevant gene and a potential target for cancer treatment. The vast majority of evidence has revealed that the deregulation of alternative splicing processes often occurs in cancer-associated genes and leads to tumorigenesis. Results: From 102 breast cancer tissue samples, we found six samples contained the 26 exon deletion FAK associated with a mutation at the 3192 bp site(CDS), but this 26 exon deletion FAK was not observed in the samples derived from 101 normal tissues. Interestingly, the 26 exon deletion FAK, which possesses the same kinase activity and biological function as wild-type FAK, is resistant to caspase-mediated cleavage and prevents breast cancer cells from apoptosis, promoting breast cancer cells survival. Conclusion: Therefore, our study revealed that the aberrant splicing of the FAK gene may promote tumorigenesis, providing a new method for diagnosing breast cancer and a potentially important target for breast cancer treatment. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-07-09.

Calpain 2 activity increases at the time of implantation in rat uterine luminal epithelial cells and administration of calpain inhibitor significantly reduces implantation sites

The present study investigated the role of calpain 2 in rat uterine luminal epithelial cells during early pregnancy. Calpain 2 is an intracellular calcium-dependent proteolytic enzyme which cleaves numerous focal adhesion proteins. Calpain 2 was concentrated along the basal cell surface of uterine luminal epithelial cells at the predicted site of focal adhesions on day 1 of pregnancy and remained unchanged at the time of implantation as observed by immunofluorescence microscopy. However, Western blotting analysis showed a marked increase in the active form and a significant decrease in the latent form of calpain 2 at the time of implantation. The increase in calpain 2 activity coincides with the disassembly of focal adhesion proteins, talin, paxillin, integrin β1 and β3 from the site of focal adhesions. Intraperitoneal injection of calpain inhibitor, calpain inhibitor l (ALLN), significantly reduced the number of implantation sites, implying that calpain 2 plays an important role in implantation. The present study suggests a role for calpain 2 in the disassembly of focal adhesions, which has been previously shown to play a key role in uterine receptivity for implantation.

The regulation of dynamic mechanical coupling between actin cytoskeleton and nucleus by matrix geometry

Cells sense their physical microenvironment and transduce these signals through actin-nuclear links to regulate nuclear functions including gene expression. However, the spatio-temporal coupling between perinuclear actin and nucleus and their functional importance are still unclear. Using micropatterned substrates to control cell geometry, we show that perinuclear actin organization at the apical plane remodels from mesh-like structure to stress fibers. The formation of these apical stress fibers (ASFs) correlated with significant reduction in nuclear height and was found to exert an active compressive load on the nucleus via direct contact with mature focal adhesion sites. Interestingly, the dynamic nature of ASFs was found to transduce forces to chromatin assembly. In addition, geometric perturbations or using pharmacological drugs to inhibit actomyosin contractility of ASFs resulted in nuclear instability. Taken together, our work provides direct evidence of physical links between the nucleus and focal adhesion sites via ASFs, which modulate nuclear homeostatic balance and internal chromatin structure. We suggest that such direct links may underlie nuclear mechanotransduction to regulate genomic programs.

Essential roles of Crk and CrkL in fibroblast structure and motility

Cytosolic proteins containing SH2 and SH3 domains, such as Crk and Crk-like (CrkL), are broadly expressed adapters that interact with a variety of proteins to fulfill key roles in signal transduction pathways triggered by activation of receptor and non-receptor tyrosine kinases. Crk and CrkL are similar to each other in structure and biochemical function, although they provide both distinct, as well as overlapping, biological roles during development. We developed a systematic approach to investigate Crk family functions at the cellular level by generating a conditional knock-out system for ablation of Crk and CrkL in cultured fibroblasts. The loss of both Crk and CrkL from fibroblasts resulted in reduced cell surface area and adoption of a rounded, refractile cellular phenotype. These morphological alterations were accompanied by a decrease in focal adhesion sites, reduced actin stress fibers and a collapse of microtubule structures. In addition, cells exhibited decreases in spontaneous motility and wound-healing behavior. Reduced p130Cas phosphorylation and actin levels closely followed the loss of Crk and CrkL, and stabilization of polymerized actin by jasplakinolide suppressed the morphological conversion. Ablation of Crk or CrkL alone conferred a much more modest phenotype suggesting that Crk and CrkL have overlapping functions that are critical for maintaining cell structure. The morphological alterations could be partially rescued by reintroduction of CrkII, and, to a lesser extent, CrkL. Taken together, our results suggest that Crk and CrkL have critical roles in cell structure and motility by maintaining cytoskeletal integrity.

Migration speed and directionality switch of normal epithelial cells after TGF-β1-induced EMT (tEMT) on micro-structured polydimethylsiloxane (PDMS) substrates with variations in stiffness and topographic patterning

The epithelial to mesenchymal transition (EMT) involves several physiological and pathological phenomena and endows cells with invasive and migratory properties. However, the effects of substrate stiffness and topography on the migration of cells before or after transforming growth factor-β1 (TGF-β1)-induced EMT (tEMT) are unknown. Herein, we seed control or tEMT NMuMG cells on the 2D patterns consisted of 1 μm or 5 μm line-widths and groove or cone patterns on either 2 MPa (1.96 ± 0.48 MPa) or 4 MPa (3.70 ± 0.74 MPa) polydimethylsiloxane (PDMS) substrates. After tEMT, the increased expression of α-SMA with vinculin in focal adhesion (FA) sites led to an acceleration of tEMT cell motility. On the 2 MPa substrate, the most influenced substrate was the 1 μm, cone-patterned substrate, where the tEMT cells' motility decelerated by 0.13 μm/min (36% slower than the cells on groove pattern). However, on the 5 μm, groove-patterned substrate, where the tEMT cells demonstrated the most rapid motility relative to the control cells, with an increment of 0.18 μm/min (100%). Among the different physical cues from substrate, the cone pattern could impede the migration speed of tEMT cells. Furthermore, we recommend the groove-patterned with a 5 μm line-width substrate as a useful tool to differentiate control and tEMT cells by migration speed.

Costamere remodeling with muscle loading and unloading in healthy young men

Costameres are mechano-sensory sites of focal adhesion in the sarcolemma that provide a structural anchor for myofibrils. Their turnover is regulated by integrin-associated focal adhesion kinase (FAK). We hypothesized that changes in content of costamere components (beta 1 integrin, FAK, meta-vinculin, gamma-vinculin) with increased and reduced loading of human anti-gravity muscle would: (i) relate to changes in muscle size and molecular parameters of muscle size regulation [p70S6K, myosin heavy chain (MHC)1 and MHCIIA]; (ii) correspond to adjustments in activity and expression of FAK, and its negative regulator, FRNK; and (iii) reflect the temporal response to reduced and increased loading. Unloading induced a progressive decline in thickness of human vastus lateralis muscle after 8 and 34 days of bedrest (−4% and −14%, respectively; n = 9), contrasting the increase in muscle thickness after 10 and 27 days of resistance training (+5% and +13%; n = 6). Changes in muscle thickness were correlated with changes in cross-sectional area of type I muscle fibers (r = 0.66) and beta 1 integrin content (r = 0.76) at the mid-point of altered loading. Changes in meta-vinculin and FAK-pY397 content were correlated (r = 0.85) and differed, together with the changes of beta 1 integrin, MHCI, MHCII and p70S6K, between the mid- and end-point of resistance training. By contrast, costamere protein level changes did not differ between time points of bedrest. The findings emphasize the role of FAK-regulated costamere turnover in the load-dependent addition and removal of myofibrils, and argue for two phases of muscle remodeling with resistance training, which do not manifest at the macroscopic level.

Expression of metastasis suppressor BRMS1 in breast cancer cells results in a marked delay in cellular adhesion to matrix

Metastatic dissemination is a multi-step process that depends on cancer cells' ability to respond to microenvironmental cues by adapting adhesion abilities and undergoing cytoskeletal rearrangement. Breast Cancer Metastasis Suppressor 1 (BRMS1) affects several steps of the metastatic cascade: it decreases survival in circulation, increases susceptibility to anoikis, and reduces capacity to colonize secondary organs. In this report, BRMS1 expression is shown to not significantly alter expression levels of integrin monomers, while time-lapse and confocal microscopy revealed that BRMS1-expressing cells exhibited reduced activation of both β1 integrin and focal adhesion kinase, and decreased localization of these molecules to sites of focal adhesions. Short-term plating of BRMS1-expressing cells onto collagen or fibronectin markedly decreased cytoskeletal reorganization and formation of cellular adhesion projections. Under 3D culture conditions, BRMS1-expressing cells remained rounded and failed to reorganize their cytoskeleton and form invasive colonies. Taken together, BRMS1-expressing breast cancer cells are greatly attenuated in their ability to respond to microenvironment changes. © 2013 Wiley Periodicals, Inc.

Crystal structure of the N‐terminal domains of the surface cell antigen 4 of Rickettsia

The obligate intracellular, gram-negative bacterium Rickettsia is the causative agent of spotted fevers and typhus in humans. Surface cell antigen (sca) proteins surround these bacteria. We recently reported the co-localization of one of these proteins, sca4, with vinculin in cells at sites of focal adhesions and demonstrated that two vinculin binding sites directed the sca4/vinculin interaction. Here we report the 2.2 Å crystal structure of the conserved N-terminal 38 kDa domain of sca4 from Rickettsia rickettsii. The structure reveals two subdomains. The first is an all-helical domain that is folded in a fashion similar to the dimeric assembly chaperone for rubisco, namely RbcX. The following and highly conserved β-strand domain lacks significant structural similarity with other known structures and to the best of our knowledge represents a new protein fold.

Quantitative changes in focal adhesion kinase and its inhibitor, FRNK, drive load-dependent expression of costamere components

Costameres are mechanosensory sites of focal adhesion in the sarcolemma that reinforce the muscle-fiber composite and provide an anchor for myofibrillogenesis. We hypothesized that elevated content of the integrin-associated regulator of costamere turnover in culture, focal adhesion kinase (FAK), drives changes in costamere component content in antigravity muscle in a load-dependent way in correspondence with altered muscle weight. The content of FAK in soleus muscle being phosphorylated at autoregulatory tyrosine 397 (FAK-pY397) was increased after 20 s of stretch. FAK-pY397 content remained elevated after 24 h of stretch-overload due to upregulated FAK content. Overexpression of FAK in soleus muscle fibers by means of gene electrotransfer increased the β1-integrin (+56%) and meta-vinculin (+88%) content. α7-Integrin (P = 0.46) and γ-vinculin (P = 0.18) content was not altered after FAK overexpression. Co-overexpression of the FAK inhibitor FAK-related nonkinase (FRNK) reduced FAK-pY397 content by 33% and increased the percentage of fast-type fibers that arose in connection with hybrid fibers with gene transfer. Transplantation experiments confirmed the association of FRNK expression with slow-to-fast fiber transformation. Seven days of unloading blunted the elevation of FAK-pY397, β1-integrin, and meta-vinculin content with FAK overexpression, and this was reversed by 1 day of reloading. The results highlight that the expression of components for costameric attachment sites of myofibrils is under load- and fiber type-related control via FAK and its inhibitor FRNK.

Axial super resolution topography of focal adhesion by confocal microscopy

The protein organization within focal adhesions has been studied by state-of-the-art super resolution methods because of its thin structure, well below diffraction limit. However, to achieve high axial resolution, most of the current approaches rely on either sophisticated optics or diligent sample preparation, limiting their application. In this report we present a phasor-based method that can be applied to fluorescent samples to determine the precise axial position of proteins using a conventional confocal microscope. We demonstrate that with about 4,000 photon counts collected along a z-scan, axial localization precision close to 10 nm is achievable. We show that, with within 10 nm, the axial location of paxillin, FAK, and talin is similar at focal adhesion sites, while F-actin shows a sharp increase in height towards the cell center. We further demonstrated the live imaging capability of this method. With the advantage of simple data acquisition and no special instrument requirement, this approach could have wide dissemination and application potentials.

Iduronic Acid in Chondroitin/Dermatan Sulfate Affects Directional Migration of Aortic Smooth Muscle Cells

Aortic smooth muscle cells produce chondroitin/dermatan sulfate (CS/DS) proteoglycans that regulate extracellular matrix organization and cell behavior in normal and pathological conditions. A unique feature of CS/DS proteoglycans is the presence of iduronic acid (IdoA), catalyzed by two DS epimerases. Functional ablation of DS-epi1, the main epimerase in these cells, resulted in a major reduction of IdoA both on cell surface and in secreted CS/DS proteoglycans. Downregulation of IdoA led to delayed ability to re-populate wounded areas due to loss of directional persistence of migration. DS-epi1−/− aortic smooth muscle cells, however, had not lost the general property of migration showing even increased speed of movement compared to wild type cells. Where the cell membrane adheres to the substratum, stress fibers were denser whereas focal adhesion sites were fewer. Total cellular expression of focal adhesion kinase (FAK) and phospho-FAK (pFAK) was decreased in mutant cells compared to control cells. As many pathological conditions are dependent on migration, modulation of IdoA content may point to therapeutic strategies for diseases such as cancer and atherosclerosis.

Integrin Upregulation and Localization to Focal Adhesion Sites in Pregnant Human Myometrium

Focal adhesions are integrin-rich microdomains that structurally link the cytoskeleton to the extracellular matrix and transmit mechanical signals. In the pregnant uterus, increases in integrin expression and activation are thought to be critical for the formation of the mechanical syncytium required for labor. The aim of this study was to determine which integrins are upregulated and localized to focal adhesions in pregnant human myometrium. We used quantitative polymerase chain reaction, Western blotting, and confocal microscopy to determine the expression levels and colocalization with focal adhesion proteins. We observed increases in several integrin transcripts in pregnant myometrium. At the protein level, integrins such as α5-integrin (ITGA5), ITGA7, ITGAV, and ITGB3 were significantly increased during pregnancy. The integrins ITGA3, ITGA5, ITGA7, and ITGB1 colocalized with focal adhesion proteins in term human myometrium. These data suggest that integrins α3β1, α5β1, and α7β1 are the most likely candidates to transmit mechanical signals from the extracellular matrix through focal adhesions in pregnant human myometrium.

In vitro and in vivo effects of short hairpin RNA targeting integrin-linked kinase in prostate cancer cells

Integrin-linked kinase (ILK) localizes at focal adhesion sites, plays an important role in cell-matrix interactions and is involved in the regulation of tumor cell growth and migration. The aim of the present study was to clarify the functional characterization of ILK in prostate cancer (PCa) cells. ILK was shown to be overexpressed in 57.1% (36/63) of PCa samples and 18.2% (2/11) of benign prostatic hyperplasia (BPH) samples using immunohistochemical analysis. DU145 PCa cells knocked down for ILK were examined using western blot analysis, proliferation assay, flow cytometry and wound healing assay. Depletion of ILK significantly impaired cell growth and motility, induced apoptosis in vitro, and delayed xenograft tumor proliferation in nude mice, which were important for oncogenesis and tumor progression. Western blot analysis showed that Akt activity was attenuated in ILK‑depleted cells compared with the control cells. These results indicate that ILK knockdown attenuates the biological behavior of PCa cells by decreasing Akt activity, demonstrating that ILK is involved in the development and progression of PCa. Thus, ILK is suggested to serve as a potential therapeutic target for PCa.

Wnt5a promotes human colon cancer cell migration and invasion but does not augment intestinal tumorigenesis in Apc 1638N mice

Whereas aberrant activation of canonical Wnt/β-catenin signaling underlies the majority of colorectal cancer cases, the contribution of non-canonical Wnt signaling is unclear. As enhanced expression of the most extensively studied non-canonical Wnt ligand WNT5A is observed in various diseases including colon cancer, WNT5A is gaining attention nowadays. Numerous in vitro studies suggest modulating capacities of WNT5A on proliferation, differentiation, migration and invasion, affecting tumor and non-mutant cells. However, a possible contribution of WNT5A to colorectal cancer remains to be elucidated. We have analyzed WNT5A expression in colorectal cancer profiling data sets, altered WNT5A expression in colon cancer cells and used our inducible Wnt5a transgenic mouse model to gain more insight into the role of WNT5A in intestinal cancer. We observed that increased WNT5A expression is associated with poor prognosis of colorectal cancer patients. WNT5A knockdown in human colon cancer cells caused reduced directional migration, deregulated focal adhesion site formation and reduced invasion, whereas Wnt5a administration promoted the directional migration of colon cancer cells. Despite these observed protumorigenic activities of WNT5A, the induction of Wnt5a expression in intestinal tumors of Apc1638N mice was not sufficient to augment malignancy or metastasis by itself. In conclusion, WNT5A promotes adhesion sites to form in a focal fashion and promotes the directional migration and invasion of colon cancer cells. Although these activities appear insufficient by themselves to augment malignancy or metastasis in Apc1638N mice, they might explain the poor colon cancer prognosis associated with enhanced WNT5A expression.

Finite Element Analysis of Traction Force Microscopy: Influence of Cell Mechanics, Adhesion, and Morphology

The interactions between adherent cells and their extracellular matrix (ECM) have been shown to play an important role in many biological processes, such as wound healing, morphogenesis, differentiation, and cell migration. Cells attach to the ECM at focal adhesion sites and transmit contractile forces to the substrate via cytoskeletal actin stress fibers. This contraction results in traction stresses within the substrate/ECM. Traction force microscopy (TFM) is an experimental technique used to quantify the contractile forces generated by adherent cells. In TFM, cells are seeded on a flexible substrate and displacements of the substrate caused by cell contraction are tracked and converted to a traction stress field. The magnitude of these traction stresses are normally used as a surrogate measure of internal cell contractile force or contractility. We hypothesize that in addition to contractile force, other biomechanical properties including cell stiffness, adhesion energy density, and cell morphology may affect the traction stresses measured by TFM. In this study, we developed finite element models of the 2D and 3D TFM techniques to investigate how changes in several biomechanical properties alter the traction stresses measured by TFM. We independently varied cell stiffness, cell-ECM adhesion energy density, cell aspect ratio, and contractility and performed a sensitivity analysis to determine which parameters significantly contribute to the measured maximum traction stress and net contractile moment. Results suggest that changes in cell stiffness and adhesion energy density can significantly alter measured tractions, independent of contractility. Based on a sensitivity analysis, we developed a correction factor to account for changes in cell stiffness and adhesion and successfully applied this correction factor algorithm to experimental TFM measurements in invasive and noninvasive cancer cells. Therefore, application of these types of corrections to TFM measurements can yield more accurate estimates of cell contractility.

LKB1 Represses Focal Adhesion Kinase (FAK) Signaling via a FAK-LKB1 Complex to Regulate FAK Site Maturation and Directional Persistence

Liver kinase β1 (LKB1, also known as STK11) is a serine/threonine kinase that has multiple cellular functions including the regulation of cell polarity and motility. Murine proteomic studies show that LKB1 loss causes aberrant adhesion signaling; however, the mechanistic underpinnings of this relationship are unknown. We show that cells stably depleted of LKB1 or its co-activator STRADα have increased phosphorylation of focal adhesion kinase (FAK) at Tyr(397)/Tyr(861) and enhanced adhesion to fibronectin. LKB1 associates in a complex with FAK and LKB1 accumulation at the cellular leading edge is mutually excluded from regions of activated Tyr(397)-FAK. LKB1-compromised cells lack directional persistence compared with wild-type cells, but this is restored through subsequent pharmacological FAK inhibition or depletion, showing that cell directionality is mediated through LKB1-FAK signaling. Live cell confocal imaging reveals that LKB1-compromised cells lack normal FAK site maturation and turnover, suggesting that defects in adhesion and directional persistence are caused by aberrant adhesion dynamics. Furthermore, re-expression of full-length wild-type or the LKB1 N-terminal domain repressed FAK activity, whereas the kinase domain or C-terminal domain alone did not, indicating that FAK suppression is potentially regulated through the LKB1 N-terminal domain. Based upon these results, we conclude that LKB1 serves as a FAK repressor to stabilize focal adhesion sites, and when LKB1 function is compromised, aberrant FAK signaling ensues, resulting in rapid FAK site maturation and poor directional persistence.

Role of dynamin 2 in the disassembly of focal adhesions

Dynamin 2 (DNM2) is involved in endocytosis and intracellular membrane trafficking through its function in vesicle formation from distinct membrane compartments. During the last decade, several studies pointed out an important role of DNM2-dependent trafficking in turnover of focal adhesions which represent a physical link between the extracellular matrix and the intracellular actin cytoskeleton, and a platform for several signalling pathways. Here, we review the involvement of DNM2 in structural and functional aspects of the focal adhesion sites. Mutations in the DNM2 gene cause two hereditary neuromuscular disorders: dominant centronuclear myopathy and Charcot-Marie-Tooth peripheral neuropathy. Potential impairment of focal adhesions as a pathophysiological hypothesis in DNM2-related human diseases is discussed.