BACKGROUND: Protein phosphatase 2A (PP2A) is a @entity563 / @entity1889 phosphatase distributed in eukaryotes from @entity375 to @entity1 , and plays pivotal roles in diverse cellular functions such as metabolism, cell cycle progression, gene expression and development. PP2A holoenzyme is a heterodimer of a catalytic subunit C and a regulatory subunit A, or a heterotrimer of C, A and a variable regulatory subunit consisting of three families; B, B', and PR72. Specific functions for each variable subunit are not well understood. RESULTS: Two @entity6739 genes pbp1+ and pbp2+ homologous to the regulatory subunit B' were isolated. Physical in vivo interaction of the gene products with the catalytic subunit was demonstrated. A double disruption haploid mutant (Deltapbp1Deltapbp2) showed growth defect, cell shape and size abnormality, multiseptation and anucleated cell formation due to abnormality in septum positioning. These phenotypes were suppressed by @entity1 B' cDNA, indicating the striking conservation of the B' function from @entity375 to @entity1 . Over-expression of @entity6739 B' led to growth defects, a loss of cell shape polarity, septal abnormality and anucleated cell formation. Deltapbp1Deltapbp2 and pbp1 null haploids were hypersensitive to calcineurin inhibitors, @entity205 and @entity1140 , with which the mutants underwent arrest at post-anaphase and cell lysis. Double disruption of calcineurin and pbp1+, but not pbp2+, genes led to synthetic lethality. CONCLUSION: The @entity6739 B' subunit of PP2A plays critical roles in cell shape control and septum formation, and shares essential functions with calcineurin for viability, possibly through their roles in cytokinesis and cell wall integrity.

XXXX homologues of the B' subunit of protein phosphatase 2A: multiple roles in mitotic cell division and functional interaction with calcineurin.

@entity1 :: ('9606', 'Species') :: ['human'] @entity6739 :: ('4896', 'Species') :: ['fission yeast'] @entity375 :: ('4932', 'Species') :: ['yeast'] @entity205 :: ('MESH:D016572', 'Chemical') :: ['cyclosporin A'] @entity563 :: ('CHEBI:17822', 'Chemical') :: ['serine'] @entity1889 :: ('CHEBI:26986', 'Chemical') :: ['threonine'] @entity1140 :: ('MESH:D016559', 'Chemical') :: ['FK506']
@entity6739 :: (4896,Species) :: ['Fission yeast']
