Hemoglobin endocytosis in Leishmania is mediated through a 46-kDa protein located in the flagellar pocket.

Sengupta, S and Tripathi, J and Tandon, R and Raje, Manoj and Roy, R P and Basu, S K and Mukhopadhyay, A (1999) Hemoglobin endocytosis in Leishmania is mediated through a 46-kDa protein located in the flagellar pocket. The Journal of biological chemistry, 274 (5). pp. 2758-65. ISSN 0021-9258

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Four lines of evidence indicate that a specific high affinity binding site on the surface of Leishmania donovani promastigotes mediates rapid internalization and degradation of hemoglobin. 1) Binding and uptake of 125I-hemoglobin by Leishmania followed saturation kinetics and were competed by unlabeled hemoglobin but not by globin or hemin or other heme- or iron-containing proteins. 2) Immunogold labeling studies revealed that, at 4 degreesC, hemoglobin binding was localized in the flagellar pocket of the promastigotes. Indirect immunofluorescence assays showed that, at 37 degreesC, the bound hemoglobin in such cells entered an endocytic compartment within 2 min and dispersed throughout the cell body by 15 min. 3) After incubation with hemoglobin-gold conjugates at 25 degreesC or 37 degreesC, the particles accumulated in discrete intracellular vesicles. 4) A single biotinylated protein of 46 kDa was revealed when solubilized membranes from surface biotinylated intact Leishmania adsorbed by hemoglobin-agarose beads were subjected to SDS-polyacrylamide gel electrophoresis and Western blotting with avidin-horseradish peroxidase. Considered together, these data indicate that this 46-kDa protein on the cell surface of L. donovani promastigotes mediates the binding of hemoglobin and its rapid internalization through a vesicular pathway characteristic of receptor-mediated endocytosis.

Item Type: Article
Additional Information: Copyright of this article belongs to ASBMB.
Subjects: Q Science > QD Chemistry
Depositing User: Dr. K.P.S.Sengar
Date Deposited: 30 Jan 2012 17:55
Last Modified: 07 Jan 2015 05:59
URI: http://crdd.osdd.net/open/id/eprint/793

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