title: Phosphocysteine in the PRL-CNNM pathway mediates magnesium homeostasis.
abstract: PRLs (phosphatases of regenerating liver) are frequently overexpressed in human cancers and are prognostic markers of poor survival. Despite their potential as therapeutic targets, their mechanism of action is not understood in part due to their weak enzymatic activity. Previous studies revealed that PRLs interact with CNNM ion transporters and prevent CNNM4-dependent Mg2+transport, which is important for energy metabolism and tumor progression. Here, we report that PRL-CNNM complex formation is regulated by the formation of phosphocysteine. We show that cysteine in the PRL catalytic site is endogenously phosphorylated as part of the catalytic cycle and that phosphocysteine levels change in response to Mg2+levels. Phosphorylation blocks PRL binding to CNNM Mg2+transporters, and mutations that block the PRL-CNNM interaction prevent regulation of Mg2+efflux in cultured cells. The crystal structure of the complex of PRL2 and the CBS-pair domain of the Mg2+transporter CNNM3 reveals the molecular basis for the interaction. The identification of phosphocysteine as a regulatory modification opens new perspectives for signaling by protein phosphatases.
authors.affiliation: Department of Biochemistry and Groupe de recherche axé sur la structure des protéines, McGill University, Montreal, Quebec, Canada.
authors.forename: Irina
authors.initials: I
authors.lastname: Gulerez
authors.affiliation: Department of Cellular Regulation, Research Institute for Microbial Diseases Osaka University, Suita, Osaka, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Funato
authors.affiliation: Department of Biochemistry and Groupe de recherche axé sur la structure des protéines, McGill University, Montreal, Quebec, Canada.
authors.forename: Howie
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Biochemistry and Groupe de recherche axé sur la structure des protéines, McGill University, Montreal, Quebec, Canada.
authors.forename: Meng
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Biochemistry and Groupe de recherche axé sur la structure des protéines, McGill University, Montreal, Quebec, Canada.
authors.forename: Guennadi
authors.initials: G
authors.lastname: Kozlov
authors.affiliation: Department of Cellular Regulation, Research Institute for Microbial Diseases Osaka University, Suita, Osaka, Japan hmiki@biken.osaka-u.ac.jp kalle.gehring@mcgill.ca.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Miki
authors.affiliation: Department of Biochemistry and Groupe de recherche axé sur la structure des protéines, McGill University, Montreal, Quebec, Canada hmiki@biken.osaka-u.ac.jp kalle.gehring@mcgill.ca.
authors.forename: Kalle
authors.identifier: 0000-0001-6500-1184
authors.initials: K
authors.lastname: Gehring
mesh_terms: D027682:Cation Transport Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D016213:Cyclins / Q000378:metabolism*; D003545:Cysteine / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006706:Homeostasis; D006801:Humans; D008274:Magnesium / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009363:Neoplasm Proteins / Q000378:metabolism; D009369:Neoplasms; D010766:Phosphorylation; D011485:Protein Binding; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: C558175:CNNM2 protein, human; D027682:Cation Transport Proteins; D018797:Cell Cycle Proteins; D016213:Cyclins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C057779:S-phosphocysteine; C490198:PTP4A1 protein, human; D017027:Protein Tyrosine Phosphatases; D008274:Magnesium; D003545:Cysteine
keywords: X‐ray crystallography; cysteine; magnesium; phosphatase; phosphorylation