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REI-1 Is a Guanine Nucleotide Exchange Factor Regulating RAB-11 Localization and Function in C. elegans Embryos.
Aisa Sakaguchi1, Miyuki Sato2, Katsuya Sato2
1Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371-8512, Japan.
Developmental Cell
|October 28, 2015
Summary
Researchers identified RAB-11-interacting protein-1 (REI-1) as a novel guanine nucleotide exchange factor (GEF) for Rab11 in C. elegans. REI-1 regulates Rab11 localization, impacting cell division and endocytic recycling in early embryos.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The small GTPase Rab11 is crucial for cellular processes like endocytic recycling, secretion, and cytokinesis.
- Upstream regulators of Rab11, particularly guanine nucleotide exchange factors (GEFs), are not fully understood.
Purpose of the Study:
- To identify novel regulators of Rab11 in Caenorhabditis elegans.
- To characterize the function of RAB-11-interacting protein-1 (REI-1) as a potential GEF for Rab11.
Main Methods:
- In vitro GEF assays to assess REI-1 activity towards Rab11.
- Analysis of REI-1 and RAB-11 localization in C. elegans embryos using microscopy.
- Phenotypic analysis of REI-1 loss-of-function mutants in C. elegans, focusing on embryonic development and cytokinesis.
Main Results:
- REI-1 and its human homolog, SH3-binding protein 5, exhibit significant GEF activity for Rab11 in vitro, despite lacking canonical GEF domains.
- REI-1 localizes to late-Golgi membranes and co-localizes with RAB-11 in the C. elegans germline.
- Loss of REI-1 disrupts RAB-11 targeting to late-Golgi and recycling endosomes, impairing its distribution to the cleavage furrow and causing cytokinesis delay in embryos.
Conclusions:
- REI-1 functions as a specific GEF for RAB-11 in C. elegans.
- REI-1 is essential for regulating RAB-11 localization and function during early embryonic development, particularly in cytokinesis.
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