ARPP-16/ARPP-19 PHOSPHORYLATION BY CDK5

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。环磷酸腺苷调节的磷酸蛋白ARPP-16和ARPP-19是哺乳动物大脑新纹状体中发现的PKA底物。除了在ARPP-19的N端多了16个残基外，这些蛋白的氨基酸序列都是相同的。这些蛋白的功能尚不清楚，尽管多巴胺强烈刺激ARPP-16的磷酸化。格林加德实验室最近的研究表明，ARPP-16和ARPP-19被CDK5/p35磷酸化。我们对体外磷酸化的蛋白质进行了蛋白质分解和质谱分析，以定位CDK5/p35的磷酸化位点。我们能够将磷酸定位到三个Ser/Thr残基中的一个，其中只有一个在cdk共识序列(S/T)P内。因此，几乎可以肯定，这个残基(ARPP-19的Ser42)是由CDK5/p35磷酸化的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cyclic-AMP regulated phosphoproteins ARPP-16 and ARPP-19 are PKA substrates found in the neostriatum of the mammalian brain. The amino acid sequences of these proteins are identical except for an extra 16 residues at the N-terminus of ARPP-19. The functions of these proteins are unknown, although phosphorylation of ARPP-16 is strongly stimulated by dopamine. Recent work in the Greengard lab has shown that ARPP-16 and ARPP-19 are phosphorylated by cdk5/p35. We analyzed the in vitro phosphorylated proteins by proteolysis and mass spectrometry to localize the site of cdk5/p35 phosphorylation. We were able to localize the phosphate to one of three Ser/Thr residues, only one of which is within the cdk consensus sequence (S/T)P. Therefore this residue (Ser42 of ARPP-19) is almost certainly phosphorylated by cdk5/p35.