Abstract
Rab GTPases are essential regulators of many cellular processes and play an important role in downstream signaling vital to proper cell function. We sought to elucidate the role of novel D. discoideum GTPase RabS. Cell lines over-expressing DdRabS and expressing DdRabS N137I (dominant negative (DN)) proteins were generated, and it was determined that DdRabS localized to endosomes, ER-Golgi membranes, and the contractile vacuole system. It appeared to function in vesicular trafficking, and the secretion of lysosomal enzymes. Interestingly, microscopic analysis of GFP-tagged DdRabS (DN) cells showed differential localization to lysosomes and endosomes compared to GFP-tagged DdRabS overexpressing cells. Both cell lines over-secreted lysosomal glycosidase enzymes, especially β-glucosidase. Furthermore, DdRabS overexpressing cells were defective in aggregation due to decreased cell–cell cohesion and sensitivity to cAMP, leading to abnormal chemotactic migration, the inability to complete development, and increased induced cell death. These data support a role for DdRabS in trafficking along the vesicular and biosynthetic pathways. We hypothesize that overexpression of DdRabS may interfere with GTP activation of related proteins essential for normal development resulting in a cascade of defects throughout these processes.
Highlights
Dictyostelium discoideum is a haploid social amoeba that has proven to be an excellent model system for studying a number of processes including adhesion, cell–cell signaling, development, host pathogen interactions, and gene regulation among others
In this study we report an investigation into the role of RabS in Dictyostelium development, endocytosis, endocytic recycling, and the secretion of lysosomal enzymes
DdRabS overexpressing cells showed a significant increase in the internalization of RITC-dextran compared to the wild type (WT) strain AX4 cells, reaching a maximum endocytic rate nearly three times that of AX4 cells after 120 min
Summary
Dictyostelium discoideum is a haploid social amoeba that has proven to be an excellent model system for studying a number of processes including adhesion, cell–cell signaling, development, host pathogen interactions, and gene regulation among others. It has three life cycles consisting of a vegetative phase, a developmental phase, and a sexually reproductive phase [1]. Biology 2018, 7, 33 unknown [3]. The movement of these proteins appears to rely on vesicular trafficking suggesting the involvement of Rab GTPases [3,4,5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
