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Inhibition of calcineurin by cyclosporin A‐cyclophilin requires calcineurin B
Author(s) -
Haddy Alice,
Swanson Selene K.-H.,
Born Timothy L.,
Rusnak Frank
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81456-v
Subject(s) - calcineurin , cyclophilin , phosphatase , protein subunit , cyclophilin a , biochemistry , chemistry , peptidylprolyl isomerase , calmodulin , enzyme , biology , microbiology and biotechnology , transplantation , isomerase , medicine , gene
The interaction of the immunosuppressive complex cyclosporin A‐cyclophilin (CsA‐CyP) with the Ca 2+ /calmodulin‐dependent protein phosphatase calcineurin is investigated using a recombinant form of the A subunit of calcineurin (rCNA). Only in the presence of purified calcineurin B (CNB) does rCNA show the response of native calcineurin, i.e. 50% inhibition of rCNA phosphatase activity at 6 nM human cyclophilin B and 0.6 μM human cyclophilin A using [ 32 P]casein as substrate, yet stimulation of activity with p ‐nitrophenyl phosphate as substrate. This study demonstrates that the B subunit is necessary to confer sensitivity of calcineurin to CsA‐CyP.