tailieunhanh - Báo cáo khoa học: Coiled–coil interactions modulate multimerization, mitochondrial binding and kinase activity of myotonic dystrophy protein kinase splice isoforms

The myotonic dystrophy protein kinase polypeptide repertoire in mice and humans consists of six different splice isoforms that vary in the nature of their C-terminal tails and in the presence or absence of an internal Val– Ser–Gly–Gly–Gly motif. Here, we demonstrate that myotonic dystrophy protein kinase isoforms exist in high-molecular-weight complexes controlled by homo- and heteromultimerization. | iFEBS Journal Coiled-coil interactions modulate multimerization mitochondrial binding and kinase activity of myotonic dystrophy protein kinase splice isoforms Rene E. M. A. van Herpen Jorrit V. Tjeertes Susan A. M. Mulders Ralph J. A. Oude Ophuis Be Wieringa and Derick G. Wansink Department of Cell Biology Nijmegen Centre for Molecular Life Sciences Radboud University Nijmegen MedicalCentre the Netherlands Keywords coiled-coildomain multimerization myotonic dystrophy protein kinase proteinprotein interaction Rho kinase family Correspondence D. G. Wansink Department of Cell Biology code 283 NCMLS Radboud University Nijmegen MedicalCentre PO Box 9101 6500 HB Nijmegen the Netherlands Fax 31 24 3615317 Tel 31 24 3613664 14329 E-mail Website http Received 24 November 2005 revised 11 January 2006 accepted 16 January 2006 doi The myotonic dystrophy protein kinase polypeptide repertoire in mice and humans consists of six different splice isoforms that vary in the nature of their C-terminal tails and in the presence or absence of an internal Val-Ser-Gly-Gly-Gly motif. Here we demonstrate that myotonic dystrophy protein kinase isoforms exist in high-molecular-weight complexes controlled by homo- and heteromultimerization. This multimerization is mediated by coiled-coil interactions in the tail-proximal domain and occurs independently of alternatively spliced protein segments or myotonic dystrophy protein kinase activity. Complex formation was impaired in myotonic dystrophy protein kinase mutants in which three leucines at positions a and d in the coiled-coil heptad repeats were mutated to glycines. These coiled-coil mutants were still capable of autophosphorylation and transphosphorylation of peptides but the rates of their kinase activities were significantly lowered. Moreover phosphorylation of the natural myotonic dystrophy protein kinase substrate myosin phosphatase targeting subunit was preserved even .