Shaw David, Wang Sandra M, Villaseñor Armando G, Tsing Stan, Walter David, Browner Michelle F, Barnett Jim, Kuglstatter Andreas
Discovery Technologies, Roche Palo Alto, 3431 Hillview Avenue, Palo Alto, CA 94304, USA.
J Mol Biol. 2008 Nov 21;383(4):885-93. doi: 10.1016/j.jmb.2008.08.086. Epub 2008 Sep 10.
c-Jun N-terminal kinase (JNK) 2 is a member of the mitogen-activated protein (MAP) kinase group of signaling proteins. MAP kinases share a common sequence insertion called "MAP kinase insert", which, for ERK2, has been shown to interact with regulatory proteins and, for p38alpha, has been proposed to be involved in the regulation of catalytic activity. We have determined the crystal structure of human JNK2 complexed with an indazole inhibitor by applying a high-throughput protein engineering and surface-site mutagenesis approach. A novel conformation of the activation loop is observed, which is not compatible with its phosphorylation by upstream kinases. This activation inhibitory conformation of JNK2 is stabilized by the MAP kinase insert that interacts with the activation loop in an induced-fit manner. We therefore suggest that the MAP kinase insert of JNK2 plays a role in the regulation of JNK2 activation, possibly by interacting with intracellular binding partners.
c-Jun氨基末端激酶（JNK）2是丝裂原活化蛋白（MAP）激酶信号蛋白家族的成员。MAP激酶共享一个称为“MAP激酶插入序列”的共同序列插入片段，对于ERK2而言，该片段已被证明可与调节蛋白相互作用，对于p38α而言，有人提出它参与催化活性的调节。我们通过应用高通量蛋白质工程和表面位点诱变方法，确定了与吲唑抑制剂复合的人JNK2的晶体结构。观察到激活环的一种新构象，该构象与其上游激酶的磷酸化不兼容。JNK2的这种激活抑制构象通过以诱导契合方式与激活环相互作用的MAP激酶插入序列而得以稳定。因此，我们认为JNK2的MAP激酶插入序列可能通过与细胞内结合伴侣相互作用，在JNK2激活的调节中发挥作用。
