Anti-BIG2 Antibody, clone 56 clone 56, from mouse

Brefeldin A-inhibited guanine nucleotide-exchange protein 2 (UniProt: Q9Y6D5; also known as Brefeldin A-inhibited GEP 2, ADP-ribosylation factor guanine nucleotide-exchange factor 2, BIG2) is encoded by the ARFGEF2 (also known as ARFGEP2, BIG2) gene (Gene ID: 10564) in human. BIG1 and BIG2, are important activators of ADP-ribosylation factors for vesicular trafficking. BIG1 and BIG2 display about 74% homology in their amino acid sequence and about 90% identity in their Sec7 domains. BIG2, contains a 200-aa Sec7 domain that is responsible for this catalytic activity and its inhibition by brefeldin A. The Sec7 domain is located near the center of the molecule and serves to accelerate replacement of GDP bound to ARF with GTP. BIG2 is expressed in placenta, lung, heart, brain, kidney and pancreas. BIG2 is shown to promote guanine-nucleotide exchange on ARF1 and ARF3 and to a lower extent on ARF5 and ARF6. It promotes the activation of ARF1/ARF5/ARF6 through replacement of GDP with GTP. BIG2 is required for the integrity of the endosomal compartment and is involved in trafficking from the trans-Golgi network (TGN) to endosomes. In vitro phosphorylation of BIG2 by PKA reduces its GEF activity. Mutations in ARFGEP2 gene are known to cause periventricular nodular heterotopia 2 (PVNH2), which is characterized by the presence of periventricular nodules of cerebral gray matter, resulting from a failure of neurons to migrate normally from the lateral ventricular proliferative zone, where they are formed, to the cerebral cortex. PVNH2 causes developmental delays and makes the subject to recurrent infections. (Ref.: Li, H et al. (2003). Proc. Natl. Acad. Sci. USA 100(4):1627-32).