title: Metal-dependent protein phosphatase 1A functions as an extracellular signal-regulated kinase phosphatase.
abstract: Protein phosphorylation is an important post-translational modification that regulates almost every aspect of signal transduction in cells. Activation of the mitogen-activated protein kinase (MAPK) family kinase extracellular signal-regulated kinase (ERK) is a point of convergence for many cellular activities in response to external stimulation. With stimuli, ERK activity is significantly increased by the phosphorylation of Thr202 and Tyr204 at its activation loop. Downregulation of ERK phosphorylation at these two sites by several phosphatases, such as protein phosphatase 2A, HePTP and MAPK phosphatase 3, is essential for maintaining appropriate ERK function in different cellular processes. However, it is unknown whether metal-dependent protein phosphatase (PPM) family phosphatases directly dephosphorylate ERK. In this study, we found that PPM1A negatively regulated ERK by directly dephosphorylating its pThr202 position early in EGF stimulation. Additional kinetic studies revealed that key residues participated in phospho-ERK recognition by PPM1A. Importantly, PPM1A preferred the phospho-ERK peptide sequence over a panel of other phosphopeptides through the interactions of basic residues in the active site of PPM1A with the pThr-Glu-pTyr motif of ERK. Whereas Lys165 and Arg33 were required for efficient catalysis or phosphosubstrate binding of PPM1A, Gln185 and Arg186 were determinants of PPM1A substrate specificity. The interaction between Arg186 of PPM1A and Glu203 and pTyr204 of phospho-ERK was identified as a hot-spot for phospho-ERK-PPM1A interaction.
authors.affiliation: Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.forename: Zheng
authors.initials: Z
authors.lastname: Gong
authors.forename: Chang
authors.initials: C
authors.lastname: Pan
authors.forename: Di-Dong
authors.initials: DD
authors.lastname: Xie
authors.forename: Jun-Yi
authors.initials: JY
authors.lastname: Tang
authors.forename: Min
authors.initials: M
authors.lastname: Cui
authors.forename: Yun-Fei
authors.initials: YF
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Yao
authors.forename: Qi
authors.initials: Q
authors.lastname: Pang
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Xu
authors.forename: Min-Yong
authors.initials: MY
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Yu
authors.forename: Jin-Peng
authors.initials: JP
authors.lastname: Sun
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D004815:Epidermal Growth Factor / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D010766:Phosphorylation / Q000235:genetics; D000071636:Protein Phosphatase 2C; D013379:Substrate Specificity / Q000235:genetics
chemical_list: D004815:Epidermal Growth Factor; D048049:Extracellular Signal-Regulated MAP Kinases; C000607456:PPM1A protein, human; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C