Calcineurin complex variant 1

Species: Saccharomyces cerevisiae (strain ATCC 204508 / S288c); 559292
Accession number: EBI-1249909


Systematic Name:


PP2B1-CANB complex calcineurin phosphatase 2B
protein phosphatase-2B serine/threonine-protein phosphatase 2B PP2B
protein phosphatase 3 PP3

A Ca2+/calmodulin-regulated Ser/Thr protein phosphatase, highly conserved through evolution and a critical component of Ca2+-regulated signaling in a wide range of unicellular and multicellular eukaryotes. Calcineurin is a heterodimer containing a catalytic (A) subunit complexed with an essential regulatory (B) subunit. Calcineurin function requires interaction of both subunits. The catalytic subunit contains an active site dinuclear metal center. The regulatory subunit is tightly associated, myristoylated and binds Ca2+ via four Ca2+-binding EF-hand motifs. Two redundant genes, CNA1 and CNA2, encode the catalytic subunit and their expression is regulated in a cell cycle-dependent manner. In the yeast, Ca2+ signaling mediated by calcineurin, is required for survival during environmental stress. One role of the phosphatase under these conditions is to activate gene expression through its regulation of the Crz1p transcription factor. Calcineurin controls many other physiological processes in yeast, including cell cycle progression, cation homeostasis, morphogenesis, establishment of cell polarity and regulation of cell wall biosynthesis. Cells deficient for calcineurin are unable to survive pheromone-induced G1 arrest. When mobilization of internal calcium stores occurs, the catalytic subunit is bound by Ca2+-calmodulin and the active site is freed by displacement of the autoinhibitory domain.


CNA1 and CNA2 are translated into proteins with predicted molecular masses of 63 and 68 kDa. The CNB1 subunit has molecular mass 19-20 kDa. The enzyme cofactors are Fe3+ and Zn2+.

Complex Assembly:



ID Name Description Stochiometry Biological Role Interactor Type Linked Features Other Features
CNB1 Calcineurin subunit B 1 unspecified role protein
binding-associated region P23287 [?-?]
CNA1 Serine/threonine-protein phosphatase 2B catalytic subunit A1 1 enzyme protein
binding-associated region P25296 [?-?]

Cross References

Type Database Identifier Description
evidence ontology ECO:0000353
biological process gene ontology GO:0006874 cellular calcium ion homeostasis
biological process gene ontology GO:0022604 regulation of cell morphogenesis
biological process gene ontology GO:0032878 regulation of establishment or maintenance of cell polarity
biological process gene ontology GO:0032995 regulation of fungal-type cell wall biogenesis
biological process gene ontology GO:0045893 positive regulation of transcription, DNA-templated
biological process gene ontology GO:0051726 regulation of cell cycle
cellular component gene ontology GO:0005955 calcineurin complex
molecular function gene ontology GO:0004722 protein serine/threonine phosphatase activity
molecular function gene ontology GO:0005509 calcium ion binding
molecular function gene ontology GO:0005516 calmodulin binding
Experimental evidence that interaction occurs intact EBI-44472
identical object in an external resource intenz
additional information pubmed 11015619
additional information pubmed 12325122
additional information pubmed 12725927
additional information pubmed 14623300