Protein phosphatase type 1 in mammalian cell mitosis: chromosomal localization and involvement in mitotic exit.
We have examined the role of protein phosphatase type 1 (PP-1) in mammalian cell mitosis. Immunofluorescence using anti-PP-1 antibodies revealed that PP-1, which is mainly localized in the cytoplasm of G1 and S phase cells, accumulates in the nucleus during G2 phase and intensely colocalizes with individual chromosomes at mitosis. This increase in nuclear PP-1 in G2/M cells was confirmed by immunoblotting on subcellular fractions. Microinjection of neutralizing anti-PP-1 antibodies before division blocked cells at metaphase, whereas injection of PP-1 in one pole of an anaphase B cell accelerated cytokinesis and the reflattening of the injected cell. These results reveal a specific cell cycle-dependent redistribution of PP-1 and its involvement in reversing p34cdc2-induced effects after mid-mitosis in mammalian cells.
Fernandez
A
A
Biochimie, Centre National de la Recherche Scientifique/Institut National de la Sante et de la Recherche Medicale, Montpellier, France.
Brautigan
D L
DL
Lamb
N J
NJ
D000818:Animals; D000906:Antibodies; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology; D002875:Chromosomes / Q000201:enzymology*; D015151:Immunoblotting; D007399:Interphase; D008677:Metaphase; D008845:Microinjections; D008938:Mitosis; D010749:Phosphoprotein Phosphatases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D051381:Rats
D000906:Antibodies; D010749:Phosphoprotein Phosphatases