Yeast protein kinase Ptk2 localizes at the plasma membrane and phosphorylates in vitro the C-terminal peptide of the H⁺-ATPase

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• 作者：Pilar Eraso ; Marí ; a J. Mazó ; n and Francisco Portillo
• 关键词：H⁺-ATPase ; Plasma membrane ; Ptk2 ; Phosphorylation ; Glucose activation
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2006
• 出版时间：February 2006
• 年：2006
• 卷：1758
• 期：2
• 页码：164-170
• 全文大小：736 K

文摘

Glucose triggers posttranslational modifications that increase the activity of the Saccharomyces cerevisiae plasma membrane H⁺-ATPase (Pma1). Glucose activation of yeast H⁺-ATPase results from the change in two kinetic parameters: an increase in the affinity of the enzyme for ATP, depending on Ser⁸⁹⁹, and an increase in the V_max involving Thr⁹¹². Our previous studies suggested that Ptk2 mediates the Ser⁸⁹⁹-dependent part of the activation. In this study we find that Ptk2 localized to the plasma membrane in a Triton X-100 insoluble fraction. In vitro phosphorylation assays using a recombinant GST-fusion protein comprising 30 C-terminal amino acids of Pma1 suggest that Ser⁸⁹⁹ is phosphorylated by Ptk2. Furthermore, we show that the Ptk2 carboxyl terminus is essential for glucose-dependent Pma1 activation and for the phosphorylation of Ser⁸⁹⁹.