Protein phosphatase-1 binding to scd5p is important for regulation of actin organization and endocytosis in yeast.
SCD5, an essential gene, encodes a protein important for endocytosis and actin organization in yeast. Previous two-hybrid screens showed that Scd5p interacts with Glc7p, a yeast Ser/Thr-specific protein phosphatase-1 (PP1) that participates in a variety of cellular processes. PP1 substrate specificity in vivo is regulated by association with different regulatory or targeting subunits, many of which have a consensus PP1-binding site ((V/I)XF, with a basic residue at the -1 or -2 position). Scd5p contains two of these potential PP1-binding motifs: KVDF (amino acids 240-243) and KKVRF (amino acids 272-276). Deletion analysis mapped the PP1-binding domain to a region of Scd5p containing these motifs. Therefore, the consequence of mutating these two potential PP1-binding sites was examined. Although mutation of KVDF had no effect, alteration of KKVRF dramatically reduced Scd5p interaction with Glc7p and resulted in temperature-sensitive growth. Furthermore, this mutation caused defects in fluid phase and receptor-mediated endocytosis and actin organization. Overexpression of GLC7 suppressed the temperature-sensitive growth of the KKVRF mutant and partially rescued the actin organization phenotype. These results provide evidence that Scd5p is a PP1 targeting subunit for regulation of actin organization and endocytosis or that Scd5p is a PP1 substrate, which regulates the function of Scd5p in these processes.
D000199:Actins / Q000378:metabolism*; D020816:Amino Acid Motifs; D001483:Base Sequence; D001665:Binding Sites; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D004705:Endocytosis; D005656:Fungal Proteins / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D011485:Protein Binding; D054645:Protein Phosphatase 1; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
D000199:Actins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D005656:Fungal Proteins; C100586:SCD5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C092048:GLC7 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1