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Identification of sds22 as an inhibitory subunit of protein phosphatase‐1 in rat liver nuclei
Author(s) -
Dinischiotu Anca,
Beullens Monique,
Stalmans Willy,
Bollen Mathieu
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(96)01514-1
Subject(s) - phosphatase , protein subunit , immunoprecipitation , protein phosphatase 1 , yeast , microbiology and biotechnology , protein phosphatase 2 , biochemistry , peptide , biology , chemistry , phosphorylation , gene
sds22 was originally identified in yeast as a regulator of protein phosphatase‐1 that is essential for the completion of mitosis. We show here that a structurally related mammalian polypeptide (41.6 kDa) is part of a 260‐kDa species of protein phosphatase‐1. This holoenzyme, designated PP‐1N sds22 , could be immunoprecipitated with sds22 antibodies and was retained by microcystin‐Sepharose. PP‐1N sds22 is a latent phosphatase, but its activity could be revealed by the proteolytic destruction of the noncatalytic subunit(s). PP‐1N sds22 accounted for only 5–10% of the total activity of PP‐1 in rat liver nuclear extracts. A synthetic 22‐mer peptide, corresponding to a leucine‐rich repeat of sds22, specifically inhibited the catalytic subunit of PP‐1, showing that at least part of the latency stems from the interaction of the sds22 repeat(s) with PP‐1 C .