In-silico identification of Tyr232 in AMPKα2 as a dephosphorylation site for the protein tyrosine phosphatase PTP-PEST

The AMP-activated protein kinase (AMPK) is known to be activated by the protein tyrosine phosphatase non-receptor type 12 (PTP-PEST) under hypoxic conditions. This activation is mediated by tyrosine dephosphorylation of the AMPK subunit. However, the identity of the phosphotyrosine residues remains unknown. In this study we first predicted the structure of the complex of the AMPK2 subunit and PTP-PEST catalytic domain using bioinformatics tools and further confirm the stability of the complex using molecular dynamics simulations. Evaluation of the protein-protein interfaces indicates that residue Tyr232 is the most likely site of dephosphorylation on AMPK2. In addition, we explored the effect of phosphorylation of PTP-PEST residue Tyr64 on the stability of the complex. The phosphorylation of Tyr64, an interface residue, enhances the stability of the complex via the rearrangement of a network of electrostatic interactions in conjunction with conformational changes in the catalytic WPD loop. Our findings present a plausible structural basis of AMPK regulation mediated by PTP-PEST and shows how phosphorylation of PTP-PEST could be involved in its activation.