title: Protein kinases CKI and CKII are implicated in modification of ribosomal proteins of the yeast Trichosporon cutaneum.
abstract: Phosphorylation of acidic ribosomal proteins P1/P2-P0 is a common phenomenon in eukaryotic organisms. It was found previously that in Trichosporon cutaneum, unlike in other yeast species, in addition to the two acidic ribosomal proteins, two other proteins of 15 kDa and 19 kDa of the small ribosomal subunit were phosphorylated. Here we describe two protein kinases: CKI and CKII, which are engaged in the modification of T. cutaneum ribosomal proteins. The acidic ribosomal proteins and the protein of 19 kDa were modified by CKII associated with ribosomes, while the protein of 15 kDa was modified by CKI. Protein kinase CKI was purified from cell-free extract (CKIC) and from ribosomal fraction (CKIR). The molecular mass of CKIC was established at 33 kDa while that of CKIR at 35-37 kDa. A protein of 40 kDa copurified with CKIR but not CKIC. Heparin significantly increased 40 kDa protein phosphorylation level by CKIR. Microsequencing analysis revealed the presence of CKI recognition motifs in the N-terminal fragment of the 40 kDa protein.
authors.affiliation: Department of Invertebrate Immunology, Institute of Biology, Maria Curie-Skłodowska University, Lublin, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Wojda
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Cytryńska
authors.forename: Magdalena
authors.initials: M
authors.lastname: Frajnt
authors.forename: Teresa
authors.initials: T
authors.lastname: Jakubowicz
mesh_terms: D000595:Amino Acid Sequence; D047390:Casein Kinase II; D047388:Casein Kinases; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010766:Phosphorylation; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000302:isolation & purification / Q000378:metabolism*; D012343:RNA, Transfer; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism; D014250:Trichosporon / Q000201:enzymology* / Q000378:metabolism
chemical_list: D012269:Ribosomal Proteins; D012343:RNA, Transfer; D011494:Protein Kinases; D047390:Casein Kinase II; D047388:Casein Kinases; D017346:Protein Serine-Threonine Kinases