title: Mutation of calcineurin subunit B M118 influences the activities of NF-AT and p53, but not calcineurin expression level.
abstract: Calcineurin (CN) is a Ca(2+)/calmodulin-dependent phosphatase, which consists of a catalytic A-subunit (CnA) and a regulatory B-subunit (CnB). Endogenous CnA and CnB have a strong corelationship in cancer cell lines. Through the introduction of CnB and its mutants in cells, we show that CnB does not increase the expression of CnA but protects it from degradation. CnB M118 is necessary for tight binding to CnA. Point mutations of CnB M118 also do not increase the expression of CnA but protect it from degradation. Furthermore, CnB M118K fails to enhance the activities of NF-AT and p53 induced by CnA in HeLa-s cells. Mutations in CnB M118 may prove to be a valuable marker in the diagnostics of some important illnesses such as Alzheimer's disease.
authors.affiliation: Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing 100875, PR China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Cheng
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Su
authors.forename: Qun
authors.initials: Q
authors.lastname: Wei
mesh_terms: D019703:Calcineurin / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D019073:HT29 Cells; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D050778:NFATC Transcription Factors / Q000378:metabolism*; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D050778:NFATC Transcription Factors; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D019703:Calcineurin