Plexin A1 (PLXNA1)

PLXN1 alone did not bind semaphorin-3A (SEMA3A), but the NRP1/PLXN1 complex had a higher affinity for SEMA3A than did NRP1 alone. While SEMA3A binding to NRP1 did not alter nonneuronal cell morphology, SEMA3A interaction with NRP1/PLXN1 complexes induced adherent cells to round up. Expression of a dominant-negative PLXN1 in sensory neurons blocked SEMA3A-induced growth cone collapse. SEMA3A treatment led to the redistribution of growth cone NRP1 and PLXN1 into clusters. Thus, the authors concluded that physiologic SEMA3A receptors consist of NRP1/PLXN1 complexes.The transmembrane protein they called NOV was identified by a cDNA found in a skeletal muscle cDNA library and shares 72% identity with SEX.