Leishmania RAB7: characterisation of terminal endocytic stages in an intracellular parasite

TY - JOUR

T1 - Leishmania RAB7

T2 - characterisation of terminal endocytic stages in an intracellular parasite

AU - Denny, Paul W

AU - Lewis, Sharon

AU - Tempero, Jane E

AU - Goulding, David

AU - Ivens, Alasdair C

AU - Field, Mark C

AU - Smith, Deborah F

N1 - Copyright 2002 Elsevier Science B.V.

PY - 2002/8/28

Y1 - 2002/8/28

N2 - Leishmania species are intracellular parasites that inhabit a parasitophorous vacuole (PV) within host macrophages and engage with the host endo-membrane network to avoid clearance from the cell. Intracellular Leishmania amastigotes exhibit a high degree of proteolytic/lysosomal activity that may assist degradation of MHC class II molecules and subsequent interruption of antigen presentation. As an aid to further analysis of the endosomal/lysosomal events that could facilitate this process, we have characterised a Leishmania homologue of the late endosomal marker, Rab7, thought to be involved in the terminal steps of endocytosis and lysosomal delivery. The Leishmania major Rab7 (LmRAB7) protein is expressed throughout the life-cycle, shows 73 and 64% identity to Trypanosoma cruzi and Trypanosoma brucei Rab7s (TcRAB7 and TbRAB7), respectively, and includes a kinetoplastid-specific insertion. The recombinant protein binds GTP and polyclonal antibodies raised against this antigen recognise structures in the region of the cell between the nucleus and kinetoplast. By immunoelectron microscopy of axenic amastigotes, Leishmania mexicana Rab7 (LmexRAB7) is found juxtaposed to and overlapping membrane structures labelled for the megasomal marker, cysteine proteinase B, confirming a late-endosomal/lysosomal localisation.

AB - Leishmania species are intracellular parasites that inhabit a parasitophorous vacuole (PV) within host macrophages and engage with the host endo-membrane network to avoid clearance from the cell. Intracellular Leishmania amastigotes exhibit a high degree of proteolytic/lysosomal activity that may assist degradation of MHC class II molecules and subsequent interruption of antigen presentation. As an aid to further analysis of the endosomal/lysosomal events that could facilitate this process, we have characterised a Leishmania homologue of the late endosomal marker, Rab7, thought to be involved in the terminal steps of endocytosis and lysosomal delivery. The Leishmania major Rab7 (LmRAB7) protein is expressed throughout the life-cycle, shows 73 and 64% identity to Trypanosoma cruzi and Trypanosoma brucei Rab7s (TcRAB7 and TbRAB7), respectively, and includes a kinetoplastid-specific insertion. The recombinant protein binds GTP and polyclonal antibodies raised against this antigen recognise structures in the region of the cell between the nucleus and kinetoplast. By immunoelectron microscopy of axenic amastigotes, Leishmania mexicana Rab7 (LmexRAB7) is found juxtaposed to and overlapping membrane structures labelled for the megasomal marker, cysteine proteinase B, confirming a late-endosomal/lysosomal localisation.

KW - Amino Acid Sequence

KW - Animals

KW - Binding Sites

KW - Cloning, Molecular

KW - Endocytosis

KW - Endosomes

KW - Genes, Protozoan

KW - Host-Parasite Interactions

KW - Leishmania major

KW - Leishmania mexicana

KW - Life Cycle Stages

KW - Lysosomes

KW - Macrophages

KW - Mice

KW - Mice, Inbred BALB C

KW - Molecular Sequence Data

KW - Molecular Weight

KW - Recombinant Proteins

KW - Sequence Alignment

KW - rab GTP-Binding Proteins

M3 - Article

C2 - 12270626

SN - 0166-6851

VL - 123

SP - 105

EP - 113

JO - MOLECULAR AND BIOCHEMICAL PARASITOLOGY

JF - MOLECULAR AND BIOCHEMICAL PARASITOLOGY

IS - 2

ER -