Qian Z, Okuhara D, Abe M K, Rosner M R
Ben May Institute for Cancer Research, University of Chicago, Chicago, Illinois 60637, USA.
J Biol Chem. 1999 Jan 15;274(3):1621-7. doi: 10.1074/jbc.274.3.1621.
ERK7, a member of the mitogen-activated protein kinase family, has a carboxyl-terminal tail that is required for ERK7 activation, cellular localization, and its ability to inhibit DNA synthesis. To identify proteins that interact with ERK7, we utilized a yeast two-hybrid screen with the COOH-terminal tail of ERK7 as bait and isolated the cDNA for a novel protein termed CLIC3. The interaction between CLIC3 and ERK7 in mammalian cells was confirmed by co-immunoprecipitation. CLIC3 has significant homology to human intracellular chloride channels 1 (NCC27/CLIC1) and 2 and bovine kidney chloride channel p64. Like NCC27/CLIC1, CLIC3 is predominantly localized in the nucleus and stimulates chloride conductance when expressed in cells. Taken together, these results suggest that CLIC3 is a new member of the human CLIC family. The observed interaction between CLIC3 and ERK7 is the first demonstration of a stable complex between a protein that activates chloride ion transport and a member of the mitogen-activated protein kinase family of signal transducers. The specific association of CLIC3 with the COOH-terminal tail of ERK7 suggests that CLIC3 may play a role in the regulation of cell growth.
ERK7是丝裂原活化蛋白激酶家族的成员之一，其羧基末端尾巴对于ERK7的激活、细胞定位及其抑制DNA合成的能力而言是必需的。为了鉴定与ERK7相互作用的蛋白质，我们以ERK7的羧基末端尾巴作为诱饵进行酵母双杂交筛选，并分离出一种名为CLIC3的新型蛋白质的cDNA。通过共免疫沉淀证实了CLIC3与ERK7在哺乳动物细胞中的相互作用。CLIC3与人类细胞内氯离子通道1（NCC27/CLIC1）和2以及牛肾氯离子通道p64具有显著的同源性。与NCC27/CLIC1一样，CLIC3主要定位于细胞核中，并且在细胞中表达时会刺激氯离子传导。综上所述，这些结果表明CLIC3是人类CLIC家族的新成员。观察到的CLIC3与ERK7之间的相互作用首次证明了激活氯离子转运的蛋白质与丝裂原活化蛋白激酶信号转导家族成员之间存在稳定的复合物。CLIC3与ERK7羧基末端尾巴的特异性结合表明CLIC3可能在细胞生长调节中发挥作用。
