Binding of enterostatin to the human neuroepithelioma cell line SK-N-MC

SK-N-MC cells were found to possess binding sites for enterostatin, a peptide with central effects on appetite and sympathetic activation of brown adipose tissue during high-fat feeding. Scatchard analyses of the binding indicated one high-affinity binding (K-d = 0.5-1.5 nM) and one low-affinity binding (K-d = 15-30 nM) for H-3-enterostatin (APGPR). I-125-YGGAPGPR showed similar binding parameters as for the low affinity binding of H-3-APGPR. Met enkephalin and beta-casomorphin(1-5) were found to displace the binding of H-3-APGPR to the SK-N-MC cells. Affinity purification of solubilized cells revealed an APGPR-binding protein estimated to 53 kDa which may represent a distinct enterostatin receptor. Cross-linking of I-125-YGGAPGPR to intact cells labeled one major protein with the same molecular size. There was no binding of enterostatin to four other human neuroblastoma/neuroepithelioma cell lines, named LMR-92, LAN#5, NB-1 #14 and SH5-SY. (C) 1998 Elsevier Science Inc.