Plasma membrane-associated small GTPase which cycles between active GTP-bound and inactive GDP-bound states. In its active state, binds to a variety of effector proteins to regulate cellular responses such as secretory processes, phagocytosis of apoptotic cells, epithelial cell polarization and growth-factor induced formation of membrane ruffles. Rac1 p21/rho GDI heterodimer is the active component of the cytosolic factor sigma 1, which is involved in stimulation of the NADPH oxidase activity in macrophages. Essential for the SPATA13-mediated regulation of cell migration and adhesion assembly and disassembly. Stimulates PKN2 kinase activity. In concert with RAB7A, plays a role in regulating the formation of RBs (ruffled borders) in osteoclasts. In glioma cells, promotes cell migration and invasion. In podocytes, promotes nuclear shuttling of NR3C2; this modulation is required for a proper kidney functioning. Required for atypical chemokine receptor ACKR2-induced LIMK1-PAK1-dependent phosphorylation of cofilin (CFL1) and for up-regulation of ACKR2 from endosomal compartment to cell membrane, increasing its efficiency in chemokine uptake and degradation. In synapses, seems to mediate the regulation of F-actin cluster formation performed by SHANK3.Isoform B has an accelerated GEF-independent GDP/GTP exchange and an impaired GTP hydrolysis, which is restored partially by GTPase-activating proteins. It is able to bind to the GTPase-binding domain of PAK but not full-length PAK in a GTP-dependent manner, suggesting that the insertion does not completely abolish effector interaction.

• GO:0030041 : actin filament polymerization
• GO:0048532 : anatomical structure arrangement
• GO:0097190 : apoptotic signaling pathway
• GO:0002093 : auditory receptor cell morphogenesis
• GO:0007411 : axon guidance
• GO:0045453 : bone resorption
• GO:0048870 : cell motility
• GO:0008283 : cell proliferation
• GO:0045216 : cell-cell junction organization
• GO:0007160 : cell-matrix adhesion
• GO:0021799 : cerebral cortex radially oriented cell migration
• GO:0090103 : cochlea morphogenesis
• GO:0048813 : dendrite morphogenesis
• GO:0071542 : dopaminergic neuron differentiation
• GO:0021831 : embryonic olfactory bulb interneuron precursor migration
• GO:0043652 : engulfment of apoptotic cell
• GO:0003382 : epithelial cell morphogenesis
• GO:0038095 : Fc-epsilon receptor signaling pathway
• GO:0038096 : Fc-gamma receptor signaling pathway involved in phagocytosis
• GO:0006972 : hyperosmotic response
• GO:0006954 : inflammatory response
• GO:0045087 : innate immune response
• GO:0035556 : intracellular signal transduction
• GO:0030032 : lamellipodium assembly
• GO:0051668 : localization within membrane
• GO:0002551 : mast cell chemotaxis
• GO:0032707 : negative regulation of interleukin-23 production
• GO:0048261 : negative regulation of receptor-mediated endocytosis
• GO:0048011 : neurotrophin TRK receptor signaling pathway
• GO:0030168 : platelet activation
• GO:0030838 : positive regulation of actin filament polymerization
• GO:0043065 : positive regulation of apoptotic process
• GO:0045740 : positive regulation of DNA replication
• GO:0010592 : positive regulation of lamellipodium assembly
• GO:0043552 : positive regulation of phosphatidylinositol 3-kinase activity
• GO:0001934 : positive regulation of protein phosphorylation
• GO:0035025 : positive regulation of Rho protein signal transduction
• GO:0030334 : regulation of cell migration
• GO:0050690 : regulation of defense response to virus by virus
• GO:0010310 : regulation of hydrogen peroxide metabolic process
• GO:0060263 : regulation of respiratory burst
• GO:0097178 : ruffle assembly
• GO:0031529 : ruffle organization
• GO:0071526 : semaphorin-plexin signaling pathway
• GO:0007264 : small GTPase mediated signal transduction
• GO:0034446 : substrate adhesion-dependent cell spreading
• GO:0031295 : T cell costimulation
• GO:0016032 : viral process
• GO:0060071 : Wnt signaling pathway, planar cell polarity pathway

Source: The Gene Ontology Consortium. Gene ontology: tool for the unification of biology. Nat. Genet.. May 2000;25(1):25-9.
World Wide Web URL: http://www.geneontology.org/

Source: Online Mendelian Inheritance in Man, OMIM®. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University (Baltimore, MD), May, 2012.
World Wide Web URL: http://omim.org/