Trafficking and release of Leishmania metacyclic HASPB on macrophage invasion

TY - JOUR

T1 - Trafficking and release of Leishmania metacyclic HASPB on macrophage invasion

AU - MacLean, Lorna M.

AU - O'Toole, Peter John

AU - Stark, Meg

AU - Marrison, Jo

AU - Seelenmeyer, Claudia

AU - Nickel, Walter

AU - Smith, Deborah F.

N1 - © 2012 Blackwell Publishing Ltd.

PY - 2012/5

Y1 - 2012/5

N2 - Proteins of the Leishmania hydrophilic acylated surface protein B (HASPB) family are only expressed in infective parasites (both extra- and intracellular stages) and, together with the peripheral membrane protein SHERP (small hydrophilic endoplasmic reticulum-associated protein), are essential for parasite differentiation (metacyclogenesis) in the sand fly vector. HASPB is a non-classically secreted protein, requiring N-terminal acylation for trafficking to and exposure on the plasma membrane. Here, we use live cell imaging methods to further explore this pathway to the membrane and flagellum. Unlike HASPB trafficking in transfected mammalian cells, we find no evidence for a phosphorylation-regulated recycling pathway in metacyclic parasites. Once at the plasma membrane, HASPB18GFP (green fluorescent protein) can undergo bidirectional movement within the inner leaflet of the membrane and on the flagellum. Transfer of fluorescent protein between the flagellum and the plasma membrane is compromised, however, suggesting the presence of a diffusion barrier at the base of the Leishmania flagellum. Full-length HASPB is released from the metacyclic parasite surface on to macrophages during phagocytosis but while expression is maintained in intracellular amastigotes, HASPB cannot be detected on the external surface in these cells. Thus HASPB may be a dual function protein that is shed by the infective metacyclic but retained internally once Leishmania are taken up by macrophages.

AB - Proteins of the Leishmania hydrophilic acylated surface protein B (HASPB) family are only expressed in infective parasites (both extra- and intracellular stages) and, together with the peripheral membrane protein SHERP (small hydrophilic endoplasmic reticulum-associated protein), are essential for parasite differentiation (metacyclogenesis) in the sand fly vector. HASPB is a non-classically secreted protein, requiring N-terminal acylation for trafficking to and exposure on the plasma membrane. Here, we use live cell imaging methods to further explore this pathway to the membrane and flagellum. Unlike HASPB trafficking in transfected mammalian cells, we find no evidence for a phosphorylation-regulated recycling pathway in metacyclic parasites. Once at the plasma membrane, HASPB18GFP (green fluorescent protein) can undergo bidirectional movement within the inner leaflet of the membrane and on the flagellum. Transfer of fluorescent protein between the flagellum and the plasma membrane is compromised, however, suggesting the presence of a diffusion barrier at the base of the Leishmania flagellum. Full-length HASPB is released from the metacyclic parasite surface on to macrophages during phagocytosis but while expression is maintained in intracellular amastigotes, HASPB cannot be detected on the external surface in these cells. Thus HASPB may be a dual function protein that is shed by the infective metacyclic but retained internally once Leishmania are taken up by macrophages.

KW - Antigens, Protozoan

KW - Cell Membrane

KW - Flagella

KW - Green Fluorescent Proteins

KW - Leishmania major

KW - Macrophages

KW - Microscopy, Fluorescence

KW - Protein Transport

KW - Protozoan Proteins

KW - Recombinant Fusion Proteins

KW - Staining and Labeling

UR - http://www.scopus.com/inward/record.url?scp=84862794244&partnerID=8YFLogxK

U2 - 10.1111/j.1462-5822.2012.01756.x

DO - 10.1111/j.1462-5822.2012.01756.x

M3 - Article

C2 - 22256896

SN - 1462-5814

VL - 14

SP - 740

EP - 761

JO - Cellular Microbiology

JF - Cellular Microbiology

IS - 5

ER -