Analysis of isoform specific function of PP1 catalytic subunits in mammalian cells using siRNA.
Protein phosphatase type 1 (PP1) is involved in the regulation of numerous cell functions in mammalian cells. The major isoforms of PP1 catalytic subunit (PP1C)alpha, gamma1 and delta have nearly identical catalytic domain, but they vary in sequences at the amino and carboxyl termini. We previously showed that PP1Calpha is highly expressed in rat hepatoma cells. To examine isoform specific function of PP1C, each isoform was depleted from HeLa cells by RNA interference. The PP1Calpha-depleted cells rounded up and showed increased cell death, indicating that PP1Calpha is essential in cell proliferation. PP1Cgamma1-depleted cells slightly rounded up and have decreased G1 phase population and increased S phase population. The PP1Cdelta-depleted cells were enlarged, and appeared flat and rich in lamellipodia. These data suggested that each PP1C isoform has non-redundant function in vivo.
Okada
Tadashi
T
Division of Biochemical Oncology and Immunology, Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo 060-0815, Japan.
Fujii
Tsubasa
T
Tanuma
Nobuhiro
N
Mitsuhashi
Shinya
S
Urano
Takeshi
T
Araki
Yoshio
Y
Shima
Hiroshi
H
Kikuchi
Kunimi
K
D015153:Blotting, Western; D020134:Catalytic Domain; D002453:Cell Cycle; D016923:Cell Death; D049109:Cell Proliferation; D005260:Female; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D010749:Phosphoprotein Phosphatases / Q000494:pharmacology*; D020033:Protein Isoforms; D054645:Protein Phosphatase 1; D034622:RNA Interference
D020033:Protein Isoforms; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1