RanBPM is an L1‐interacting protein that regulates L1‐mediated mitogen‐activated protein kinase activation

Abstract
A yeast two‐hybrid screen using the last 28 amino acids of the cytoplasmic domain of the neural cell adhesion molecule L1 identified RanBPM as an L1‐interacting protein. RanBPM associates with L1 in vivo and the N‐terminal region of RanBPM (N‐RanBPM), containing the SPRY domain, is sufficient for the interaction with L1 in a glutathione S‐transferase pull‐down assay. L1 antibody patching dramatically changes the subcellular localization of N‐RanBPM in transfected COS cells. Overexpression of N‐RanBPM in COS cells reduces L1‐triggered extracellular signal‐regulated kinase 1/2 activation by 50% and overexpression of N‐RanBPM in primary neurons inhibits L1‐mediated neurite outgrowth and branching. These data suggest that RanBPM is an adaptor protein that links L1 to the extracellular signal‐regulated kinase/MAPK pathway.