Characterization of a polymorphic family of integral membrane proteins in promastigotes of different Leishmania species

Symons, F. M.; Murray, Peter J.; Ji, Hong; Simpson, Richard J.; Osborn, Amelia H.; Cappai, Roberto; Handman, Emanuela

doi:10.1016/0166-6851(94)90100-7

Cited by 32 publications

(35 citation statements)

References 25 publications

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“…It is now clear that glycoprotein gp46/M-2 belongs to a family of genes expressed in most Leishmania species [130,131]. Immunization of mice with membrane glycoprotein gp46/M-2 has been demonstrated to provide significant protection in mice against challenge infection with L. amazonensis [128,132,133].…”

Section: Psa-2/gp46/m-2mentioning

confidence: 99%

Vaccine candidates for leishmaniasis: A review

Nagill

Kaur

2011

International Immunopharmacology

109

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Section: Psa-2/gp46/m-2mentioning

confidence: 99%

Vaccine candidates for leishmaniasis: A review

Nagill

Kaur

2011

International Immunopharmacology

109

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“…Cells were solubilized in 40 ml of 0.5% (v/v) Triton X-114 in ice-cold PBS pH 7.3 in the presence of a mixture of protease inhibitors. After detergent phase separation, the water phase, which included all the water-soluble cytoplasmic proteins, was loaded onto the column and PSA-2 was eluted with 0.1 M glycine HCl pH 2.6 as previously described (19). The pH of the eluate was neutralized and eluted protein was quantitated using the BCA Protein Assay (Pierce, Rockford, IL) according to the manufacturer's instructions and its purity was assessed by SDS-PAGE and silver staining.…”

Section: Purification Of Water Soluble Psa-2mentioning

confidence: 99%

A Leucine-Rich Repeat Motif of Leishmania Parasite Surface Antigen 2 Binds to Macrophages through the Complement Receptor 3

Kędzierski

Montgomery

Bullen

et al. 2004

The Journal of Immunology

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Membrane glycoconjugates on the Leishmania parasites, notably leishmanolysin and lipophosphoglycan, have been implicated in attachment and invasion of host macrophages. However, the function of parasite surface Ag 2 (PSA-2) and membrane proteophosphoglycan (PPG) has not been elucidated. In this study we demonstrate that native and recombinant Leishmania infantum PSA-2, which consists predominantly of 15 leucine-rich repeats (LRR) and a recombinant LRR domain derived from L. major PPG, bind to macrophages. The interaction is restricted to macrophages and appears to be calcium independent. We have investigated the PSA-2-macrophage interaction to identify the host receptor involved in binding and we show that binding of PSA-2 to macrophages can be blocked by Abs to the complement receptor 3 (CR3, Mac-1). Data derived from mouse macrophage studies were further confirmed using cell lines expressing human CR3, and showed that PSA-2 also binds to the human receptor. This is the first demonstration of a functional role for PSA-2. Our data indicate that in addition to leishmanolysin and lipophosphoglycan, parasite attachment and invasion of macrophages involve a third ligand comprising the LRRs shared by PSA-2 and PPG and that these interactions occur via the CR3.

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“…Gp63 has been shown to be proteolytically active against a wide variety of different peptide substrates and has been reported to act as a ligand for macrophage receptors, either directly or after opsonization with complement, to protect the parasites from complementmediated lysis and also to contribute to the pathology of lesion development (see Alexander and Russell, 1992;Joshi et al, 1998). However, the fact that these proteins are encoded by multicopy polymorphic genes (Button et al, 1989;Lohman et al, 1990;Symons et al, 1994) has hindered elucidation of their function by genetic analysis (Joshi et al, 1998). Moreover, surface expression of gp63 and PSA2 is dramatically down-regulated in the amastigote stage of some Leishmania species and variable within particular parasite populations of others (Bahr et al, 1993;Handman et al, 1995) such that the precise function of these parasite proteins in the mammalian host remains unclear.…”

mentioning

confidence: 99%

Leishmania mexicanaMutants Lacking Glycosylphosphatidylinositol (GPI):Protein Transamidase Provide Insights into the Biosynthesis and Functions of GPI-anchored Proteins

Hilley

Zawadzki

McConville

et al. 2000

MBoC

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The major surface proteins of the parasitic protozoon Leishmania mexicana are anchored to the plasma membrane by glycosylphosphatidylinositol (GPI) anchors. We have cloned the L. mexicana GPI8 gene that encodes the catalytic component of the GPI:protein transamidase complex that adds GPI anchors to nascent cell surface proteins in the endoplasmic reticulum. Mutants lacking GPI8 (⌬GPI8) do not express detectable levels of GPI-anchored proteins and accumulate two putative protein-anchor precursors. However, the synthesis and cellular levels of other nonprotein-linked GPIs, including lipophosphoglycan and a major class of free GPIs, are not affected in the ⌬GPI8 mutant. Significantly, the ⌬GPI8 mutant displays normal growth in liquid culture, is capable of differentiating into replicating amastigotes within macrophages in vitro, and is infective to mice. These data suggest that GPI-anchored surface proteins are not essential to L. mexicana for its entry into and survival within mammalian host cells in vitro or in vivo and provide further support for the notion that free GPIs are essential for parasite growth. INTRODUCTIONLeishmania are protozoan parasites that cause a spectrum of diseases in humans. These parasites alternate between a flagellated promastigote stage that proliferates within the midgut of the sandfly vector and a nonmotile amastigote stage that invades mammalian macrophages, where they occupy the phagolysosome compartment. The cell surface of the promastigote stage is coated by a protective glycocalyx that comprises a number of glycosylphosphatidylinositol (GPI)-anchored glycoproteins, a complex GPI-anchored lipophosphoglycan (LPG), and a family of free GPIs (termed glycoinositolphospholipids [GIPLs]) Beverley and Turco, 1998; Figure 1). Components in this glycoclayx are thought to be essential for parasite survival and infectivity in the diverse host Beverley and Turco, 1998). The GPIanchored glycoproteins include an abundant metalloproteinase, termed gp63 or leishmanolysin, and the promastigote surface antigen (PSA2)/gp46 family of glycoproteins Murray et al., 1989;Frommel et al., 1990;Lohman et al., 1990). Gp63 has been shown to be proteolytically active against a wide variety of different peptide substrates and has been reported to act as a ligand for macrophage receptors, either directly or after opsonization with complement, to protect the parasites from complementmediated lysis and also to contribute to the pathology of lesion development (see Alexander and Russell, 1992;Joshi et al., 1998). However, the fact that these proteins are encoded by multicopy polymorphic genes (Button et al., 1989;Lohman et al., 1990;Symons et al., 1994) has hindered elucidation of their function by genetic analysis (Joshi et al., 1998). Moreover, surface expression of gp63 and PSA2 is dramatically down-regulated in the amastigote stage of some Leishmania species and variable within particular parasite populations of others (Bahr et al., 1993;Handman et al., 1995) such that the precise function of these parasite pro...

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Characterization of a polymorphic family of integral membrane proteins in promastigotes of different Leishmania species

Cited by 32 publications

References 25 publications

Vaccine candidates for leishmaniasis: A review

Vaccine candidates for leishmaniasis: A review

A Leucine-Rich Repeat Motif of Leishmania Parasite Surface Antigen 2 Binds to Macrophages through the Complement Receptor 3

Leishmania mexicanaMutants Lacking Glycosylphosphatidylinositol (GPI):Protein Transamidase Provide Insights into the Biosynthesis and Functions of GPI-anchored Proteins

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