Lack of Abundance of Cytoplasmic Cyclosporin A-binding Protein Renders Free-living Leishmania donovani Resistant to Cyclosporin A*
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
Lack of Abundance of Cytoplasmic Cyclosporin A-binding Protein Renders Free-living Leishmania donovani Resistant to Cyclosporin A*
|
|
| Creator |
Dutta, Madhuri
Delhi, Praveen Sinha, Krishna M Banerjee, Rahul Dutta, Alok K |
|
| Subject |
Chemistry
|
|
| Description |
The majority of the effects of cyclosporin A (CsA) on
cells is caused by the inhibition of phosphatase activity
of calcineurin (CN) by the cyclophilin A (CyPA)-CsA
complex formed in the cytoplasm. Although CsA inhibits
the proliferation of a large number of parasites, not all
are susceptible. The presence of structurally altered
CyPA with lower affinity for CsA had been suggested to
be the cause of resistance. We report here the identification
and cloning of a high affinity CsA-binding protein
(LdCyP) from Leishmania donovani, a trypanosomatid
parasite that is naturally resistant to CsA. The translated
LdCyP consists of 187 amino acids with a cleavable
21-amino acid hydrophobic NH2-terminal extension.
Modeling studies confirmed that all the residues of human
CyPs responsible for interaction with CsA are sequentially
and conformationally conserved in LdCyP.
The purified recombinant protein displayed biochemical
parameters comparable to human CyPs. Reverse
transcription-polymerase chain reaction analysis confirmed
that LdCyP was abundantly expressed. Immunoblot
experiments and direct CsA binding studies revealed
that LdCyP located in the subcellular organelles
constituted the bulk of the CsA binding activity present
in L. donovani, whereas the level of binding activity in
the cytosol was conspicuously low. CsA selectively facilitated the secretion of LdCyP in the culture medium.
Based on these results, it is concluded that the insensitivity of L. donovani to CsA is probably due to the paucity of CsA binding activity in the cytoplasm of the parasite. We suggest that LdCyP, located in the secretory
pathway, may function as a chaperone by binding to
membrane proteins rather than as the mediator of CN
inhibition.
|
|
| Date |
2001
|
|
| Type |
Article
PeerReviewed |
|
| Format |
application/pdf
|
|
| Identifier |
http://www.eprints.iicb.res.in/898/1/JOURNAL_OF_BIOLOGICAL_CHEMISTRY%2C_276_(_22)%2C__19294%2D19300[36].pdf
Dutta, Madhuri and Delhi, Praveen and Sinha, Krishna M and Banerjee, Rahul and Dutta, Alok K (2001) Lack of Abundance of Cytoplasmic Cyclosporin A-binding Protein Renders Free-living Leishmania donovani Resistant to Cyclosporin A*. The Journal of Biological Chemistry, 276 (22). pp. 19294-19300. |
|
| Relation |
http://dx.doi.org/10.1074/jbc.M009379200
http://www.eprints.iicb.res.in/898/ |
|