Bagella L, MacLachlan T K, Buono R J, Pisano M M, Giordano A, De Luca A
Department of Pathology, Anatomy and Cell Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
J Cell Physiol. 1998 Nov;177(2):206-13. doi: 10.1002/(SICI)1097-4652(199811)177:2<206::AID-JCP2>3.0.CO;2-R.
The cdc2-family of serine/threonine kinases and their binding partners recently were implicated in developmental roles. We previously cloned a cdc2-related kinase, cdk9/PITALRE, that is able to phosphorylate the retinoblastoma protein in vitro. We describe here the cloning and the characterization of the mouse homolog of cdk9/PITALRE. The murine cDNA is 98% identical with humans and is expressed at high levels in brain and kidney tissues. The kinase activity and protein expression of cdk9/PITALRE were highest in terminally differentiated tissues such as the muscle and brain. In situ immunohistology and immunofluorescence detected cdk9/PITALRE protein not only within terminally differentiated cells such as muscle and neuronal cells, but also in proliferating cells. C2C12 and P19 cells induced to differentiate along muscle and neural lineages peaked in cdk9/PITALRE kinase activity at the end of differentiation. These results suggest that, among other roles, cdk9/PITALRE plays a role not unlike cdk5 in the differentiation of certain cell types.
丝氨酸/苏氨酸激酶的cdc2家族及其结合伴侣最近被认为在发育过程中发挥作用。我们之前克隆了一种与cdc2相关的激酶cdk9/PITALRE，它能够在体外磷酸化视网膜母细胞瘤蛋白。我们在此描述cdk9/PITALRE小鼠同源物的克隆和特性。小鼠cDNA与人类的同源性为98%，并在脑和肾组织中高水平表达。cdk9/PITALRE的激酶活性和蛋白表达在终末分化组织如肌肉和脑中最高。原位免疫组织学和免疫荧光检测发现cdk9/PITALRE蛋白不仅存在于终末分化细胞如肌肉和神经细胞中，也存在于增殖细胞中。沿肌肉和神经谱系诱导分化的C2C12和P19细胞在分化末期cdk9/PITALRE激酶活性达到峰值。这些结果表明，除其他作用外，cdk9/PITALRE在某些细胞类型的分化中发挥着与cdk5类似的作用。
