NSP-A

GWB-108FC5

Mon 161

Each vial contains 100 ?l 1 mg/ml purified antibody in PBS containing 0. 09% sodium azide. Recently. a novel gene family has been identified and characterized. designated the Reticulons because the proteins encoded by these genes are anchored to the membranes of the endoplasmic reticulum. Reticulon-1 was formerly designated NSP for Neuroendocrine-Specific-Protein. because it is specifically expressed in neural and neuroendocrine tissues. The NSP-gene has been mapped by fluorescence in situ hybridization to human chromosome 14q21-q22. The NSP-gene encodes three overlapping proteins. i. e. Reticulon-1A (NSPA). Reticulon-1B (NSP-B). and Reticulon-1C (NSPC). These proteins were found to be anchored to membranes of the endoplasmic reticulum through their common carboxy-terminal regions. Reticulon- 1A is a protein with a molecular weight (MW) of about 135 kDa. which occurs in various isoforms presumably depending on the degree of phosphorylation of serine residues. In lung cancer diagnosis Reticulon-1A appeared to be a reliable marker for the detection of neuroendocrine differentiation. since most of the small cell lung carcinoma (SCLC) and carcinoid tumors showed expression of Reticulon-1A. Reticulon-1B is a phosphoprotein with a MW of 45 kDa and is restricted to the lung cancer cell line NCI-H82. Reticulon-1B is sofar not found in human tissues. Reticulon-1C is a protein with a MW of 23 kDa which is not phosphorylated and is found with Reticulon-1A in SCLC (cell lines) and not in non- SCLC (cell cultures).

Endoplasmic reticulum membrane; Multi-pass membrane protein.

Isoforms RTN1-A and RTN1-B are phosphorylated.