Factors responsible for the Ca2+‐dependent inactivation of calcineurin in brain

FEBS Letters

Klee, Claude B.¹  Krinks, Marie H.¹  Wang, Xutong¹  Stemmer, Paul M.¹ 

[1] Laboratory of Biochemistry, National Cancer Institute, NIH, Bethesda, MD 20892, USA

关键词: Calmodulin;    Calcineurin;    Protein phosphatase;    Ca2+;   

DOI  :  10.1016/0014-5793(95)01095-V

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The Ca²⁺-dependent protein phosphatase activity of crude rat brain extracts measured in the presence of okadaic acid, exhibits the characteristic properties of the calmodulin-stimulated protein phosphatase, calcineurin. It is stimulated more than 200-fold by Ca²⁺ and inhibited by the calmodulin-binding peptide, M13, and by the immunosuppressive drug, FK506. It is insensitive to rapamycin at concentrations up to 1 μM. Its specific activity, based on calcineurin concentration determined by quantitative analysis of Western blots exposed to anti-bovine brain IgG, is ten to twenty times that of purified rat brain calcineurin assayed under similar conditions. Unlike the purified enzyme it is rapidly and irreversibly inactivated in a time-, temperature-, and Ca²⁺/calmodulin-dependent fashion without evidence of extensive proteolytic degradation. The enzyme is converted to a state which does not lose activity by removal of low molecular weight material by gel filtration. Reconstitution of a labile enzyme is achieved by the addition of the low molecular weight-containing fraction eluted from the gel filtration column. These observations indicate that calcineurin in crude brain extracts is under the control of Ca²⁺/calmodulin-dependent positive and negative regulatory mechanisms which involve unidentified endogenous factor(s).

【 授权许可】

Unknown