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	Enzymatic activity and substrate specificity of mitogen-activated protein kinase p38 alpha in different phosphorylation states
	Zhang, Yuan-Yuan ; Mei, Zi-Qing ; Wu, Jia-Wei ; Wang, Zhi-Xin
	2010-05-11 ; 2010-05-11
关键词	SIGNAL-REGULATED KINASE-2 CONTINUOUS SPECTROPHOTOMETRIC ASSAY TYROSINE-PHOSPHATASE HEPTP MAP-KINASE KINETIC-MECHANISM PATHWAYS STRESS P38 THREONINE DEPHOSPHORYLATION Biochemistry & Molecular Biology
中文摘要	The mitogen-activated protein (MAP) kinases are essential signaling molecules that mediate many cellular effects of growth factors, cytokines, and stress stimuli. Full activation of the MAP kinases requires dual phosphorylation of the Thr and Tyr residues in the TXY motif of the activation loop by MAP kinase kinases. Down-regulation of MAP kinase activity can be initiated by multiple serine/threonine phosphatases, tyrosine-specific phosphatases, and dual specificity phosphatases (MAP kinase phosphatases). This would inevitably lead to the formation of monophosphorylated MAP kinases. However, the biological functions of these monophosphorylated MAP kinases are currently not clear. In this study, we have prepared MAP kinase p38 alpha, a member of the MAP kinase family, in all phosphorylated forms and characterized their biochemical properties. Our results indicated the following: (i) p38 alpha phosphorylated at both Thr-180 and Tyr-182 was 10-20-fold more active than p38 alpha phosphorylated at Thr-180 only, whereas p38 alpha phosphorylated at Tyr-182 alone was inactive; (ii) the dual-specific MKP5, the tyrosine-specific hematopoietic protein-tyrosine phosphatase, and the serine/threonine-specific PP2C alpha are all highly specific for the dephosphorylation of p38 alpha, and the dephosphorylation rates were significantly affected by different phosphorylated states of p38 alpha; (iii) the N-terminal domain of MPK5 has no effect on enzyme catalysis, whereas deletion of the MAP kinase-binding domain in MKP5 leads to a 370-fold decrease in kcat/Km for the dephosphorylation of p38 alpha. This study has thus revealed the quantitative contributions of phosphorylation of Thr, Tyr, or both to the activation of p38 alpha and to the substrate specificity for various phosphatases.
语种	英语 ; 英语
出版者	AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC ; BETHESDA ; 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA
内容类型	期刊论文
源URL	[http://hdl.handle.net/123456789/26562]
专题	清华大学
推荐引用方式 GB/T 7714	Zhang, Yuan-Yuan,Mei, Zi-Qing,Wu, Jia-Wei,et al. Enzymatic activity and substrate specificity of mitogen-activated protein kinase p38 alpha in different phosphorylation states[J],2010, 2010.
APA	Zhang, Yuan-Yuan,Mei, Zi-Qing,Wu, Jia-Wei,&Wang, Zhi-Xin.(2010).Enzymatic activity and substrate specificity of mitogen-activated protein kinase p38 alpha in different phosphorylation states..
MLA	Zhang, Yuan-Yuan,et al."Enzymatic activity and substrate specificity of mitogen-activated protein kinase p38 alpha in different phosphorylation states".(2010).

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