Exchange factor for GTP-binding proteins RhoA, RhoG and, to a lesser extent, Rac1. Binds physically to the nucleotide-free states of those GTPases (By similarity). Plays an important role in angiogenesis. Its recruitment by phosphorylated EPHA2 is critical for EFNA1-induced RAC1 GTPase activation and vascular endothelial cell migration and assembly. May be important for integrin-mediated signaling, at least in some cell types. In osteoclasts, along with SYK tyrosine kinase, required for signaling through integrin alpha-v/beta-1 (ITAGV-ITGB1), a crucial event for osteoclast proper cytoskeleton organization and function. This signaling pathway involves RAC1, but not RHO, activation. Necessary for proper wound healing. In the course of wound healing, required for the phagocytotic cup formation preceding macrophage phagocytosis of apoptotic neutrophils. Responsible for integrin beta-2-mediated macrophage adhesion and, to a lesser extent, contributes to beta-3-mediated adhesion. Does not affect integrin beta-1-mediated adhesion. Interacts with the PH domain of APS. Interacts with ROS1; constitutive interaction that mediates VAV3 phosphorylation (By similarity). Interacts (via SH2 domains) with the phosphorylated form of EPHA2. Abundantly expressed in osteoclasts and mature osteoblasts. Also expressed in bone marrow macrophages (at protein level):. Phosphorylated. Phosphorylation can be mediated by ROS1 (By similarity). In osteoclasts, undergoes tyrosine phosphorylation in response to CSF1. Mutant mice exhibit increased bone density, due to diminished bone resorption, including following parathyroid hormone treatment. This phenotype is due to defective terminal osteoclast differentiation. They also show a delayed wound repair program, characterized by a deficit in macrophage emigration to the wound, a reduced myofibroblast-dependent wound contraction and a diminished neovascularization in the restoration tissue. Produced by alternative promoter usage. Produced by alternative splicing.