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The Functional Significance of Phospho‐Rab GTPases (LB194)
Author(s) -
Lepore Dante,
Collins Ruth
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb194
Subject(s) - rab , gtpase , microbiology and biotechnology , phosphorylation , biology , intracellular , phosphorylation cascade , small gtpase , organelle , protein phosphorylation , protein kinase a , signal transduction
Intracellular membrane trafficking is an essential and conserved process throughout eukaryotes. To preserve organelle identity in a complex cellular system, control mechanisms must exist to oversee the production and targeting of intracellular vesicles. Key control elements are the Rab GTPases, which utilize a nucleotide‐bound cycle to act as master regulators for each discrete trafficking step. Several studies, including global proteomic screens, have identified multiple Rabs as phosphoproteins, but the functional consequence(s) of this modification are unknown. The Saccharomyces cerevisiae Rab GTPase Sec4p is negatively regulated by phosphorylation, but the molecular mechanisms and proteins responsible for this modification are unknown. Using Sec4p as a model for Rab phosphorylation and unique antibodies able to specifically detect modified Sec4p, we have shown that phosphorylation is tightly regulated in conjunction with cell cycle progression and spatial location within the cell. Currently, we are performing an overexpression screen to elucidate the kinase that modifies Sec4p as well as the biochemical pathway responsible for activating Sec4p phosphorylation. We hypothesize that Rab phosphorylation may be a novel regulatory mechanism through which additional cellular processes can impinge upon membrane trafficking. Grant Funding Source : National Institute of Health