Molecular characterization and immunolocalization of Dictyostelium discoideum protein phosphatase 2A.
Protein phosphatase 2A (PP2A) was previously purified from Dictyostelium and biochemically characterized. The purified PP2A holoenzyme was composed of a 37 kDa catalytic 'C-subunit', a 65 kDa 'A-subunit' and a 55 kDa 'B-subunit'. We report here the characterization of the genes encoding the Dictyostelium PP2A subunits as well as the immunolocalization of the PP2A subunits in Dictyostelium. The cDNAs encoding the B- and C-subunits were isolated from a Dictyostelium library and the deduced amino acid sequences reveal strong conservation with the mammalian PP2A homologues. Southern blot analysis suggests that each of the PP2A subunit genes is present in a single copy. The PP2A subunits were localized mainly to the cytosol in Dictyostelium cells. However, immunofluorescence confocal microscopy demonstrates that the B-subunit of PP2A is highly enriched in centrosomes, suggesting a potential role for this PP2A regulatory subunit in the centrosomal function.
Murphy
M B
MB
Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970, USA.
Levi
S K
SK
Egelhoff
T T
TT
D000595:Amino Acid Sequence; D000818:Animals; D015139:Blotting, Southern; D020134:Catalytic Domain; D004023:Dictyostelium / Q000201:enzymology* / Q000254:growth & development; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D017125:Genes, Protozoan; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D054648:Protein Phosphatase 2; D017386:Sequence Homology, Amino Acid
D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2