title: Human myotonic dystrophy protein kinase effect in S. cerevisiae.
abstract: Human myotonic dystrophy protein kinase (DMPK), the product of the myotonic dystrophy (DM) locus, is a member of a novel class of multidomain serine-threonine protein kinases, which interacts with members of the Rho family of small GTPases. DMPK has been shown to affect the cell growth, size and shape in different organisms, from fission yeast to man, but its physiological role is still unclear. We examined the effect of the overexpression of two forms of human DMPK, full-length (DMFL) and a C-terminal truncated form (DMT) on the growth and cell morphology of S. cerevisiae, which possesses a DMPK homologous gene (CBK1) important for polarized growth and cell division. We report that the overexpression of either forms of human DMPK did not complement the CBK1 function in the haploid strain WR208-1a, deleted for CBK1. The truncated form, but not the full length one, slowed down growth rate and induced elongation of the haploid wild type strain CBK1. Similar results were obtained in the diploid wild type strain RS112 of S. cerevisiae where also the full-length form was effective. These effects were abolished when either DMFL or DMT were mutated in the ATP binding site (K100R mutation), suggesting that the kinase activity of DMPK is required. Interestingly, DMPK localization in yeast is similar to that of Cbk1 protein suggesting that it might affect a pathway, which regulates cell morphogenesis and progression through cell cycle, possibly involving CBK1.
authors.affiliation: Institute of Clinical Physiology, National Council of Research, Via Moruzzi 1, 56100 Pisa, Italy. rdc@ifc.cnr.it
authors.forename: Renata
authors.initials: R
authors.lastname: Del Carratore
authors.forename: Francesca
authors.initials: F
authors.lastname: Ciucci
authors.forename: Pascale
authors.initials: P
authors.lastname: Beffy
authors.forename: Marta
authors.initials: M
authors.lastname: Casella
authors.forename: Mariarita
authors.initials: M
authors.lastname: Puntoni
authors.forename: Silvana
authors.initials: S
authors.lastname: Simi
authors.forename: Marcella
authors.initials: M
authors.lastname: Simili
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002455:Cell Division; D003001:Cloning, Molecular; D017931:DNA Primers; D004171:Diploidy; D004926:Escherichia coli / Q000201:enzymology; D006238:Haploidy; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D065636:Myotonin-Protein Kinase; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D017384:Sequence Deletion
chemical_list: C585517:DMPK protein, human; D017931:DNA Primers; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D065636:Myotonin-Protein Kinase; D017346:Protein Serine-Threonine Kinases