Ras-GTPase Activating Domain of IQ motif containing GTPase activating protein 1
IQGAP1 is a homodimeric protein that is widely expressed among vertebrate cell types from early embryogenesis. Mammalian IQGAP1 protein is the best characterized member of the IQGAP family, and contains several protein-interacting domains. Human IQGAP1 is most similar to mouse Iqgap1 (94% identity) and has 62% identity to human IQGAP2. IQGAP1 binds and cross-links actin filaments in vitro and has been implicated in Ca2+/calmodulin signaling, E-cadherin-dependent cell adhesion, cell motility, and invasion. Yeast IQGAP homologs have a role in the recruitment of actin filaments, are components of the spindle pole body, and are required for actomyosin ring assembly and cytokinesis. Furthermore, IQGAP1 over-expression has also been detected in gastric and colorectal carcinomas and gastric cancer cell lines.