High impact information on SDS22

• EGP1 is essential for cell growth but becomes dispensable upon overexpression of the GLC7 gene [1].
• The nucleotide sequence of EGP1 predicts a leucine-rich repeat protein that is similar to Sds22, a protein from the fission yeast Schizosaccharomyces pombe that positively modulates PP1 [1].
• Interestingly, the combination of equimolar amounts of Ypi1 and Sds22 leads to an almost full inhibition of Glc7 activity [2].
• These phenotypes mimic those produced upon inactivation of Sds22 [2].
• Similar leucine-rich repeats present in a series of other proteins, e.g., the mammalian ribonuclease/angiogenin inhibitor, adenylyl cyclase from S. cerevisiae, the toll protein from Drosophila melanogaster, and the sds22 protein phosphatase regulatory subunit from S. pombe, are thought to be involved in protein-protein interactions [3].

Biological context of SDS22

• Essential functions of Sds22p in chromosome stability and nuclear localization of PP1 [4].
• Sds22p is a conserved, leucine-rich repeat protein that interacts with the catalytic subunit of protein phosphatase 1 (PP1(C)) and which has been proposed to regulate one or more functions of PP1(C) during mitosis [4].
• Temperature-sensitive (Ts(-)) S. cerevisiae sds22 mutants show profound chromosome instability at elevated growth temperatures but do not confer a cell cycle stage-specific arrest [4].
• Two genes involved in protein phosphatase activity were identified: YCN2 and an open reading frame encoding a protein that shares 46% amino acid identity with the sds22+ protein from Schizosaccharomyces pombe [5].
• sds22 is a regulatory subunit of protein phosphatase-1 that is required for the completion of mitosis in yeast [6].

Anatomical context of SDS22

• The objectives of this study were to determine: 1) stoichiometry of PP1gamma2-sds22 binding and 2) whether PP1gamma2 in immotile caput epididymal spermatozoa is bound to sds22 [7].

Associations of SDS22 with chemical compounds

• Many of the mutants are deficient in binding two V/IXF-containing subunits, Gac1 and Reg1, which regulate glycogen accumulation and glucose repression, respectively, but all retain the ability to associate with Sds22, a regulatory subunit that lacks this motif [8].

Physical interactions of SDS22

• These results demonstrate that Sds22p forms a complex with Glc7p and that Sds22p:Glc7p is a stable isolatable form of yeast PP1 [9].

Other interactions of SDS22

• YPI1 and SDS22 Proteins Regulate the Nuclear Localization and Function of Yeast Type 1 Phosphatase Glc7 [2].

Analytical, diagnostic and therapeutic context of SDS22

• SDS-PAGE of these purified fractions revealed that in caudal sperm, the 88-kDa species is composed of sds22 (43 kDa) and PP1gamma2 (39 kDa), suggesting a 1:1 complex between these two proteins [7].
• Fluorescence immunocytochemistry was used to determine the intrasperm localization of PP1gamma2 and sds22 [10].

References