Cloning of rat ARHGAP4/C1, a RhoGAP family member expressed in the nervous system that colocalizes with the Golgi complex and microtubules

Brain Res Mol Brain Res. 2002 Oct 30;107(1):65-79. doi: 10.1016/s0169-328x(02)00448-5.

Abstract

The Rho GTPase family of intracellular molecular switches control multiple cellular functions via the regulation of the actin cytoskeleton. Increasing evidence implicates a critical involvement of these molecules in the nervous system, particularly during neuronal migration and polarity, axon and growth cone guidance, dendritic arborization and synaptic formation. However, the molecules regulating Rho GTPase activities in the nervous system are less known. Here, we present the cloning of rat ARHGAP4, a member of the Rho GTPase activating protein family, and also demonstrate its close linkage to the vasopressin 2 receptor gene. In vitro, recombinant ARHGAP4 stimulated the GTPase activity of three members of Rho GTPases, Rac1, Cdc42 and RhoA. ARHGAP4 mRNA expression was observed in multiple tissues with marked expression throughout the developing and adult nervous systems. On closer analysis of protein levels, ARHGAP4 was significantly restricted to specific regions in the nervous system. These included the stratum lucidem in the CA3 area of the hippocampus, neuronal fibers in the ventral region of the brainstem and striatum, and in the cerebellar granule cells. Subcellularly, endogenous ARHGAP4 expression localized to the Golgi complex and could redistribute to the microtubules, for example during mitosis. In addition, distinct protein expression was observed in the tips of differentiating neurites of PC12 cells. Collectively, these results demonstrate that ARHGAP4 is more widely expressed than previously thought but potentially possesses specialized activity in regulating members of the Rho GTPase family in specific cellular compartments of the nervous system.

MeSH terms

  • Amino Acid Sequence / genetics
  • Animals
  • Base Sequence / genetics
  • Cells, Cultured
  • Central Nervous System / cytology
  • Central Nervous System / embryology
  • Central Nervous System / metabolism*
  • Cloning, Molecular
  • Female
  • Fetus
  • GTPase-Activating Proteins / genetics
  • GTPase-Activating Proteins / isolation & purification*
  • Gene Expression Regulation, Developmental / genetics*
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • Immunohistochemistry
  • Male
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Molecular Sequence Data
  • Neurons / cytology
  • Neurons / metabolism*
  • Presynaptic Terminals / metabolism
  • Presynaptic Terminals / ultrastructure
  • Rats
  • Rats, Sprague-Dawley
  • cdc42 GTP-Binding Protein / genetics
  • cdc42 GTP-Binding Protein / metabolism
  • rac1 GTP-Binding Protein / genetics
  • rac1 GTP-Binding Protein / metabolism
  • rho GTP-Binding Proteins / genetics
  • rho GTP-Binding Proteins / isolation & purification
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / metabolism

Substances

  • Arhgap4 protein, rat
  • GTPase-Activating Proteins
  • cdc42 GTP-Binding Protein
  • rac1 GTP-Binding Protein
  • rho GTP-Binding Proteins
  • rhoA GTP-Binding Protein

Associated data

  • GENBANK/AF401635