Identification of two calcineurin B-binding proteins: Tubulin and heat shock protein 60

Wei Li, Robert E. Handschumacher

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Calcineurin (CaN) is a Ca++/calmodulin-dependent protein phosphatase with two subunits: a catalytic subunit (CaNA) and a regulatory subunit (CaNB). With four Ca++-binding sites and a sequence homology to calmodulin, CaNB has been defined as the regulatory subunit for CaNA. However, we have shown that mitochondrial expression of CaNB far exceeds that of CaNA. To investigate the role of this excess CaNB, we have generated glutathione-S-transferase-CaNB (GST-CaNB) fusion protein and demonstrated that the fusion protein predominantly bound to alpha-tubulin, a 57 kDa protein in bovine brain extracts, and heat shock protein 60 (Hsp60) in bovine kidney extracts. Their Ca++-dependent interactions with CaNB were verified by immunoprecipitation. The binding of CaNB could be demonstrated with purified alpha/beta tubulins and Hsp60, but not GroEL, a bacterial Hsp60 analog. The interaction of CaNB and Hsp60 was not disrupted by the incubation with Hsp10, ATP and Mg++, suggesting that CaNB was not associated with Hsp60 as a misfolded substrate, and may serve as a regulatory protein. Thus, CaNB may play other regulatory roles in Ca++-dependent events in addition to its interaction with CaNA, and may be important for Ca++-dependent processes in mitochondria.

Original languageEnglish (US)
Pages (from-to)72-81
Number of pages10
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Volume1599
Issue number1-2
DOIs
StatePublished - Sep 23 2002
Externally publishedYes

Fingerprint

Chaperonin 60
Calcineurin
Tubulin
Carrier Proteins
Calmodulin
Proteins
Fusion reactions
Mitochondria
Bacterial Proteins
Phosphoprotein Phosphatases
Sequence Homology
Glutathione Transferase
Immunoprecipitation
Brain
Catalytic Domain
Adenosine Triphosphate
Binding Sites
Kidney
Substrates

Keywords

  • Calcineurin
  • Heat shock protein 60
  • Hsp60
  • Tubulin

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Genetics

Cite this

Identification of two calcineurin B-binding proteins : Tubulin and heat shock protein 60. / Li, Wei; Handschumacher, Robert E.

In: Biochimica et Biophysica Acta - Proteins and Proteomics, Vol. 1599, No. 1-2, 23.09.2002, p. 72-81.

Research output: Contribution to journalArticle

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