Li Ke, Zhao Shuqing, Karur Vinit, Wojchowski Don M
Immunobiology Program and the Department of Veterinary Science, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Biol Chem. 2002 Dec 6;277(49):47052-60. doi: 10.1074/jbc.M205374200. Epub 2002 Sep 27.
DYRKs are a new family of dual-specificity tyrosine-regulated kinases with emerging roles in cell growth and development. Recently, we discovered that DYRK3 is expressed primarily in erythroid progenitor cells and modulates late erythropoiesis. We now describe 1) roles for the DYRK3 YTY signature motif in kinase activation, 2) the coupling of DYRK3 to cAMP response element (CRE)-binding protein (CREB), and 3) effects of DYRK3 on hematopoietic progenitor cell survival. Regarding the DYRK3 kinase domain, intactness of Tyr(333) (but not Tyr(331)) within subdomain loop VII-VIII was critical for activation. Tyr(331) plus Tyr(333) acidification (Tyr mutated to Glu) was constitutively activating, but kinase activity was not affected substantially by unique N- or C-terminal domains. In transfected 293 and HeLa cells, DYRK3 was discovered to efficiently stimulate CRE-luciferase expression, to activate a CREB-Gal4 fusion protein, and to promote CREB phosphorylation at Ser(133). Interestingly, this CREB/CRE response was also supported (50% of wild-type activity) by a kinase-inactive DYRK3 mutant as well as a DYRK3 C-terminal region and was blocked by protein kinase A inhibitors, suggesting functional interactions between protein kinase A and DYRK3. Finally, DYRK3 expression in cytokine-dependent hematopoietic FDCW2 cells was observed to inhibit programmed cell death. Thus, primary new insight into DYRK3 kinase signaling routes, subdomain activities, and possible biofunctions is provided.
双重特异性酪氨酸调节激酶（DYRKs）是一个新的激酶家族，在细胞生长和发育中发挥着越来越重要的作用。最近，我们发现DYRK3主要在红系祖细胞中表达，并调节晚期红细胞生成。我们现在描述：1）DYRK3的YTY特征基序在激酶激活中的作用；2）DYRK3与环磷酸腺苷反应元件（CRE）结合蛋白（CREB）的偶联；3）DYRK3对造血祖细胞存活的影响。关于DYRK3激酶结构域，亚结构域环VII-VIII内的酪氨酸（Tyr）（333）（而非Tyr（331））的完整性对于激活至关重要。Tyr（331）加上Tyr（333）酸化（Tyr突变为Glu）具有组成性激活作用，但激酶活性不受独特的N端或C端结构域的显著影响。在转染的293和HeLa细胞中，发现DYRK3能有效刺激CRE-荧光素酶表达，激活CREB-Gal4融合蛋白，并促进CREB在丝氨酸（Ser）（133）处的磷酸化。有趣的是，这种CREB/CRE反应也受到激酶失活的DYRK3突变体以及DYRK3 C端区域的支持（为野生型活性的50%），并被蛋白激酶A抑制剂阻断，这表明蛋白激酶A与DYRK3之间存在功能相互作用。最后，观察到细胞因子依赖性造血FDCW2细胞中DYRK3的表达可抑制程序性细胞死亡。因此，本文提供了对DYRK3激酶信号通路、亚结构域活性及可能的生物学功能的初步新见解。
