Hemoglobin receptor in Leishmania is a hexokinase located in the flagellar pocket

Krishnamurthy, Ganga ; Vikram, Rajagopal ; Singh, Sudha B. ; Patel, Nitin ; Agarwal, Shruti ; Mukhopadhyay, Gauranga ; Basu, Sandip K. ; Mukhopadhyay, Amitabha (2005) Hemoglobin receptor in Leishmania is a hexokinase located in the flagellar pocket Journal of Biological Chemistry, 280 (7). pp. 5884-5891. ISSN 0021-9258

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Official URL: http://www.jbc.org/content/280/7/5884.abstract

Related URL: http://dx.doi.org/10.1074/jbc.M411845200


Hb endocytosis in Leishmania is mediated through a 46-kDa protein located in the flagellar pocket. To understand the nature of the Hb receptor (HbR), we have purified the 46-kDa protein to homogeneity from Leishmania promastigote membrane. Purified HbR specifically binds Hb. The gene for HbR was cloned, and sequence analysis of the full-length HbR gene indicates the presence of hexokinase (HK) signature sequences, ATP-binding domain, and PTS-II motif. Four lines of evidence indicate that HbR in Leishmania is a hexokinase: 1) the recombinant HbR binds Hb, and the Hb-binding domain resides in the N terminus of the protein; 2) recombinant proteins and cell lysate prepared from HbR-overexpressing Leishmania promastigotes show enhanced HK activity in comparison with untransfected cells; 3) immunolocalization studies using antibodies against the N-terminal fragment (Ld-HbR-ΔC) of Ld-HbR indicate that this protein is located in the flagellar pocket of Leishmania; and 4) binding and uptake of 125I-Hb by Leishmania is significantly inhibited by anti-Ld-HbR-ΔC antibody and Ld-HbR-ΔC, respectively. Taken together, these results indicate that HK present in the flagellar pocket of Leishmania is involved in Hb endocytosis.

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Source:Copyright of this article belongs to American Society for Biochemistry and Molecular Biology.
ID Code:1812
Deposited On:08 Oct 2010 12:26
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