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Ca2+ and calmodulin-dependent protein phosphatase from Leishmania donovani

Published online by Cambridge University Press:  01 June 1999

C. BANERJEE ,
D. SARKAR  and
A. BHADURI
C. BANERJEE
Affiliation:
Leishmania Division, Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Calcutta 700 032, India
D. SARKAR
Affiliation:
Department of Cell Biology, Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Calcutta 700 032, India
A. BHADURI
Affiliation:
Leishmania Division, Indian Institute of Chemical Biology, 4 Raja S C Mullick Road, Calcutta 700 032, India
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Abstract

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A protein phosphatase exclusively dependent upon micromolar amounts of Ca2+ and calmodulin has been identified and partially purified from Leishmania spp. Complete obliteration of its activity is observed in the presence of calmodulin antagonists such as trifluoperazine, fluphenazine and calmidazolium. Relative insensitivity to okadaic acid and lack of activation in the absence of Ca2+ and calmodulin distinguishes this enzyme from PP1, PP2A and PP2C-type protein phosphatases. Cross-reactivity of the enzyme was observed with antibodies that recognize both the A and B chains of calcineurin, a PP2B type Ca2+ and calmodulin-dependent phosphatase from brain. FK506, an immunosuppresive drug that inhibits the enzyme from other sources inhibited the enzyme only in the presence of exogenous FK binding protein, whereas Cyclosporin A inhibited the enzyme in crude preparations. Taken together these results reveal the presence of a Ca2+ and calmodulin-dependent phosphatase from Leishmania. This is the first report of the presence of a PP2B-type protein phosphatase from a pathogenic protozoa.

Keywords

Leishmania spp.protein phosphatase 2BpromastigoteFK506visceral leishmaniasisdephosphorylationcyclosporin A
Type
Research Article
Information
Parasitology , Volume 118 , Issue 6 , June 1999 , pp. 567 - 573
Copyright
1999 Cambridge University Press