Lach E B, Broad S, Rozengurt E
Imperial Cancer Research Fund, London, United Kingdom.
Cell Growth Differ. 1995 Nov;6(11):1427-35.
The rat neuromedin B (NMB) receptor was expressed in Rat-1 fibroblasts to elucidate the signaling pathways and mitogenic effects mediated by this seven-transmembrane domain receptor. Receptor expression was verified by ligand binding and Ca2+ mobilization, which were blocked by the NMB receptor antagonist D-Nal-Cys-Tyr-D-Trp-Orn-Val-Cys-Nal-NH2. NMB acted as a potent growth factor promoting DNA synthesis and cell proliferation in serum-free medium in Rat-1 cells transfected with the NMB receptor. Prior to DNA synthesis, NMB stimulated phosphorylation of 80K/MARCKS, a major substrate of protein kinase C, which could be prevented by the selective protein kinase C inhibitor GF 109203X. Furthermore, NMB induced a rapid p42MAPK activation and tyrosine phosphorylation of multiple proteins including p125FAK and paxillin. The half-maximal concentrations (EC50) of NMB required to induce DNA synthesis (0.7-0.9 nM) and cell proliferation (0.7-1 nM) paralleled the Kd for 125I-[D-Tyr0]NMB binding and the EC50 values for the induction of the early signaling events. Thus, NMB can activate multiple signal transduction pathways and act as a sole mitogen through its receptor expressed in Rat-1 fibroblasts.
将大鼠神经介素B（NMB）受体在大鼠-1成纤维细胞中表达，以阐明由这种七跨膜结构域受体介导的信号通路和促有丝分裂作用。通过配体结合和Ca2+动员验证受体表达，这两种作用均被NMB受体拮抗剂D-Nal-Cys-Tyr-D-Trp-Orn-Val-Cys-Nal-NH2阻断。在转染了NMB受体的大鼠-1细胞的无血清培养基中，NMB作为一种有效的生长因子，促进DNA合成和细胞增殖。在DNA合成之前，NMB刺激了蛋白激酶C的主要底物80K/MARCKS的磷酸化，这可被选择性蛋白激酶C抑制剂GF 109203X阻止。此外，NMB诱导了快速的p42MAPK激活以及包括p125FAK和桩蛋白在内的多种蛋白质的酪氨酸磷酸化。诱导DNA合成（0.7 - 0.9 nM）和细胞增殖（0.7 - 1 nM）所需的NMB的半数最大浓度（EC50）与125I-[D-Tyr0]NMB结合的Kd以及早期信号事件诱导的EC50值平行。因此，NMB可以激活多种信号转导通路，并通过其在大鼠-1成纤维细胞中表达的受体作为唯一的促有丝分裂原发挥作用。
