Red1p, a MEK1-dependent phosphoprotein that physically interacts with Hop1p during meiosis in yeast.
The synaptonemal complex (SC) is a proteinaceous structure formed between pairs of homologous chromosomes during prophase I of meiosis. The proper assembly of axial elements (AEs), lateral components of the SC, during meiosis in the yeast, Saccharomyces cerevisiae, is essential for wild-type levels of recombination and for the accurate segregation of chromosomes at the first meiotic division. Genetic experiments have indicated that the stoichiometry between two meiosis-specific components of AEs in S. cerevisiae, HOP1 and RED1, is critical for proper assembly and function of the SC. A third meiosis-specific gene, MEK1, which encodes a putative serine/threonine protein kinase, is also important for proper AE function, suggesting that AE formation is regulated by phosphorylation. In this paper, we demonstrate that Mek1p is a functional kinase in vitro and that catalytic activity is an essential part of the meiotic function of Mek1 in vivo. Immunoblot analysis revealed that Red1p is a MEK1-dependent phosphoprotein. Co-immunoprecipitation experiments demonstrated that the interaction between Hop1p and Red1p is enhanced by the presence of MEK1. Thus, MEK1-dependent phosphorylation of Red1p facilitates the formation of Hop1p/Red1p hetero-oligomers, thereby enabling the formation of functional AEs.
de los Santos
T
T
Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, SUNY Stony Brook, Stony Brook, New York 11794-5215, USA.
Hollingsworth
N M
NM
D000483:Alleles; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D005816:Genetic Complementation Test; D005838:Genotype; D048369:MAP Kinase Kinase 1; D008540:Meiosis; D020929:Mitogen-Activated Protein Kinase Kinases; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C086672:HOP1 protein, S cerevisiae; C086673:RED1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases