The erythrocyte membrane cytoskeletal protein, 4.1R, is an important structural element of red blood cells. It contains a spectrin-actin-binding domain (SABD) that facilitates spectrin interaction with F-actin and a membrane-binding domain (MBD) that links the cytoskeleton to the plasma membrane via interactions with Band 3 protein. Two homologues of 4.1R, 4.1G and 4.1N, are expressed throughout the body and in neurons, respectively. These 4.1 proteins contain Ca2+-dependent (CD-CaM) and Ca2+-independent calmodulin (CI-CaM) binding sites within the MBD domain, a centrally located SABD, and a conserved C-terminal domain (CTD). 4.1N expression is high throughout the adult brain and lower in heart, kidney, and pancreas. In neurons, 4.1N protein co-localizes with PSD-95 and GluR1 at sites of synaptic contacts and the CTD of 4.1N allows binding to the C-terminus of GluR1. In addition, 4.1N interacts with the PI3-Kinase enhancer (PIKE) protein and translocates to the nucleus along with PIKE in response to NGF treatment. Thus, 4.1N is a neuronal membrane cytoskeletal protein that may be involved with localizaton of proteins such as neurotransmitter receptors and signaling molecules. Predominant isoforms of 4.1 proteins have been reported to be observable between 30-210 kD due to complex alternative splicing events. 4.1N has been reported to be observable in a range of 100-135 kD in neuronal populations.
This antibody is routinely tested by western blot analysis. Other applications were tested at BD Biosciences Pharmingen during antibody development only or reported in the literature.
