title: TRPM7 regulates myosin IIA filament stability and protein localization by heavy chain phosphorylation.
abstract: Deregulation of myosin II-based contractility contributes to the pathogenesis of human diseases, such as cancer, which underscores the necessity for tight spatial and temporal control of myosin II activity. Recently, we demonstrated that activation of the mammalian alpha-kinase TRPM7 inhibits myosin II-based contractility in a Ca(2+)- and kinase-dependent manner. However, the molecular mechanism is poorly defined. Here, we demonstrate that TRPM7 phosphorylates the COOH-termini of both mouse and human myosin IIA heavy chains--the COOH-terminus being a region that is critical for filament stability. Phosphorylated residues were mapped to Thr1800, Ser1803 and Ser1808. Mutation of these residues to alanine and that to aspartic acid lead to an increase and a decrease, respectively, in myosin IIA incorporation into the actomyosin cytoskeleton and accordingly affect subcellular localization. In conclusion, our data demonstrate that TRPM7 regulates myosin IIA filament stability and localization by phosphorylating a short stretch of amino acids within the alpha-helical tail of the myosin IIA heavy chain.
authors.affiliation: Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Kristopher
authors.initials: K
authors.lastname: Clark
authors.forename: Jeroen
authors.initials: J
authors.lastname: Middelbeek
authors.forename: Edwin
authors.initials: E
authors.lastname: Lasonder
authors.forename: Natalya G
authors.initials: NG
authors.lastname: Dulyaninova
authors.forename: Nick A
authors.initials: NA
authors.lastname: Morrice
authors.forename: Alexey G
authors.initials: AG
authors.lastname: Ryazanov
authors.forename: Anne R
authors.initials: AR
authors.lastname: Bresnick
authors.forename: Carl G
authors.initials: CG
authors.lastname: Figdor
authors.forename: Frank N
authors.initials: FN
authors.lastname: van Leeuwen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D006801:Humans; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D018995:Myosin Heavy Chains / Q000378:metabolism*; D024507:Nonmuscle Myosin Type IIA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D016415:Sequence Alignment; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D050053:TRPM Cation Channels; D010769:Phosphothreonine; D010768:Phosphoserine; D024507:Nonmuscle Myosin Type IIA; D018995:Myosin Heavy Chains