Phosphatidylinositol 3,4,5-trisphosphate-dependent guanine nucleotide exchange factor (GEF) which, independently of RAS, transduces signals from tyrosine kinase receptors to RAC. It also mediates signaling of membrane ruffling. Regulates the actin cytoskeleton as an effector or adapter protein in response to agonist stimulated phosphatidylinositol (3,4)-bisphosphate production and cell protrusion.
Expressed only in mature B-cells including those associated with mucosa-associated tissue and bronchus-associated tissue (PubMed:10681448). Widely expressed. Abundant in spleen, and fairly abundant in kidney, lung and liver. Also found in monocytes and macrophages (PubMed:12925760).
Contains 1 PH domain.
The PH domain is essential for phosphatidylinositol 3,4,5-trisphosphate binding.
Cytoplasm. Cell membrane. Nucleus. Cell projection > lamellipodium. In resting B-cells it is localized mainly in the cytoplasm and upon cell activation it is recruited to the plasma membrane and then translocates to the nucleus. In activated, class-switching B-cells it is associated with membrane IgG but not IgM. Localized to loose actin filament arrays located behind actively extending lamellipodia.