Spatial Cycling of Rab GTPase, Driven by the GTPase Cycle, Controls Rab's Subcellular Distribution

Biochemistry. 2019 Jan 29;58(4):276-285. doi: 10.1021/acs.biochem.8b00932. Epub 2019 Jan 11.

Abstract

Rab GTPases (>60 members in humans) function as master regulators of intracellular membrane trafficking. Correct and specific localization of Rab proteins is required for their function. How the distinct spatial distribution of Rab GTPases in the cell is regulated remains elusive. To globally assess the subcellular localization of Rab1, we determined kinetic parameters of two pathways that control the spatial cycles of Rab1, i.e., vesicular transport and GDP dissociation inhibitor (GDI)-mediated recycling. We demonstrate that the switching between GTP and GDP binding states, which is governed by guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), GDI, and GDI displacement factor (GDF), is a major determinant of Rab1's ability to effectively cycle between cellular compartments and eventually its subcellular distribution. In silico perturbations of vesicular transport, GEFs, GAPs, GDI, and GDF using a mathematical model with simplified cellular geometries showed that these regulators play an important role in the subcellular distribution and activity of Rab1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Computer Simulation
  • Cytoplasm / metabolism*
  • Fluorescence Recovery After Photobleaching / methods
  • GTP-Binding Proteins / genetics
  • GTP-Binding Proteins / metabolism
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism*
  • Guanine Nucleotide Exchange Factors / metabolism
  • Guanosine Diphosphate / metabolism
  • Guanosine Triphosphate / metabolism
  • HeLa Cells
  • Humans
  • Models, Theoretical
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Nocodazole / pharmacology
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism
  • rab1 GTP-Binding Proteins / genetics
  • rab1 GTP-Binding Proteins / metabolism*

Substances

  • Guanine Nucleotide Exchange Factors
  • Nerve Tissue Proteins
  • Recombinant Proteins
  • TRAPPC4 protein, human
  • Vesicular Transport Proteins
  • Guanosine Diphosphate
  • Guanosine Triphosphate
  • GTP-Binding Proteins
  • RABAC1 protein, human
  • rab1 GTP-Binding Proteins
  • Nocodazole