Collapsin

The CRMP proteins were originally identified as mediators of Sema3A (Collapsin) signaling and neuronal differentiation. Collapsin acts primarily as a repulsive axonal guidance cue and can cause a dramatic collapse of the growth cone lamillipodium which results in the formation of F-actin cytoskeleton and endocytosis of the growth cone cell membrane. A number of CRMP genes were identified and are known by different nomenclature, Turn on after division (TOAD-64), dihydropyrimidinase related protein 1 (DRP1), unc33 like protein (Ulip) and TUC (TOAD-64, Ulip, CRMP). At least 5 vertebrate CRMP proteins have been identified (CRMP1-5). The axon guidance and outgrowth protein collapsin response mediator protein 2 (CRMP2) has been linked to NMDAR trafficking and may be involved in neuronal survival following excitotoxicity (1). CRMP1-4 shared about 75% sequence homology whereas CRMP5 is only 50% homologous and also referred as CRAM. CRMP1-4 are expressed in multiple splice variants (1). In CNS, the CRMPs are expressed in developing brain specially peaked during periods od active neuronal growth (1).CRMP1 has two separate regulatory regions one of the N-terminal upper lobe of CRMP1 monomer termed as activation lobe. The CRMP1 tetramer is assembled is a way that the activation lobe lies on the surface of the protein allowing for other factors for regulation. The CRMP1 protein is phosphorylated at the C-terminal end of protein by different kinases including CdK5, GSK3b and ROCK. Disruption in SemaA3 signaling or changes in CRMP activity resulted in devastating developmental neurological disorders. Highly CRMP2 phosphorylated form is often observed in Alzheimer’s disease (2). CRMP1-4 can all bind to tubulin in vitro and in brain, and are expressed in immature interneurons in the adult olfactory bulb, a site of ongoing neurogenesis in adult hood (3). CRMP1 gene is located on chromosome 8p21.2-p21.1 and expressed a protein of 71kDa MW. The CRMP1-selective antibodies were generated against peptide taken from within the unique N-terminal region between amino acid 80-124 of the CRMP1 protein. The CRMP1-selective antibodies are affinity purified over immobilized antigen based affinity chromatography which yielded high affinity epitope-specific antibodies. The CRMP1 antibodies label a protein of approximately 90kDa band on Western blot using Western blot positive control for CRMP1 (PC-CRMP1). The CRMP1-selective antibodies are also available in FITC conjugated preparations for confocal and direct immunocytochemical localization of CRMP1 protein. FabGennix Inc. will also conjugate antibodies to many other fluorescent probes upon request at a nominal charge. Limited quantities of antigenic blocking peptide and western blot positive controls are also available (inquire before ordering). FabGennix Inc. has an inventory of more than 1100 well characterized antibodies for research and diagnostic applications, for a complete listing please visit www.FabGennix.com.