The human cytomegalovirus US28 protein is located in endocytic vesicles and undergoes constitutive endocytosis and recycling
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The human cytomegalovirus US28 protein is located in endocytic vesicles and undergoes constitutive endocytosis and recycling. / Fraile-Ramos, A; Kledal, T N; Pelchen-Matthews, A; Bowers, K; Schwartz, T W; Marsh, M.
In: Molecular Biology of the Cell, Vol. 12, No. 6, 2001, p. 1737-49.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The human cytomegalovirus US28 protein is located in endocytic vesicles and undergoes constitutive endocytosis and recycling
AU - Fraile-Ramos, A
AU - Kledal, T N
AU - Pelchen-Matthews, A
AU - Bowers, K
AU - Schwartz, T W
AU - Marsh, M
N1 - Keywords: Animals; Blotting, Western; CHO Cells; COS Cells; Cell Membrane; Chemokine CX3CL1; Chemokines, CX3C; Cricetinae; Cytomegalovirus; DNA, Complementary; Down-Regulation; Endocytosis; Endosomes; Fibroblasts; Hela Cells; Humans; Ligands; Membrane Proteins; Microscopy, Electron; Microscopy, Fluorescence; Receptors, Chemokine; Temperature; Time Factors; Viral Proteins
PY - 2001
Y1 - 2001
N2 - Genes encoding chemokine receptor-like proteins have been found in herpes and poxviruses and implicated in viral pathogenesis. Here we describe the cellular distribution and trafficking of a human cytomegalovirus (HCMV) chemokine receptor encoded by the US28 gene, after transient and stable expression in transfected HeLa and Cos cells. Immunofluorescence staining indicated that this viral protein accumulated intracellularly in vesicular structures in the perinuclear region of the cell and showed overlap with markers for endocytic organelles. By immunogold electron microscopy US28 was seen mostly to localize to multivesicular endosomes. A minor portion of the protein (at most 20%) was also expressed at the cell surface. Antibody-feeding experiments indicated that cell surface US28 undergoes constitutive ligand-independent endocytosis. Biochemical analysis with the use of iodinated ligands showed that US28 was rapidly internalized. The high-affinity ligand of US28, the CX(3)C-chemokine fractalkine, reduced the steady-state levels of US28 at the cell surface, apparently by inhibiting the recycling of internalized receptor. Endocytosis and cycling of HCMV US28 could play a role in the sequestration of host chemokines, thereby modulating antiviral immune responses. In addition, the distribution of US28 mainly on endosomal membranes may allow it to be incorporated into the viral envelope during HCMV assembly.
AB - Genes encoding chemokine receptor-like proteins have been found in herpes and poxviruses and implicated in viral pathogenesis. Here we describe the cellular distribution and trafficking of a human cytomegalovirus (HCMV) chemokine receptor encoded by the US28 gene, after transient and stable expression in transfected HeLa and Cos cells. Immunofluorescence staining indicated that this viral protein accumulated intracellularly in vesicular structures in the perinuclear region of the cell and showed overlap with markers for endocytic organelles. By immunogold electron microscopy US28 was seen mostly to localize to multivesicular endosomes. A minor portion of the protein (at most 20%) was also expressed at the cell surface. Antibody-feeding experiments indicated that cell surface US28 undergoes constitutive ligand-independent endocytosis. Biochemical analysis with the use of iodinated ligands showed that US28 was rapidly internalized. The high-affinity ligand of US28, the CX(3)C-chemokine fractalkine, reduced the steady-state levels of US28 at the cell surface, apparently by inhibiting the recycling of internalized receptor. Endocytosis and cycling of HCMV US28 could play a role in the sequestration of host chemokines, thereby modulating antiviral immune responses. In addition, the distribution of US28 mainly on endosomal membranes may allow it to be incorporated into the viral envelope during HCMV assembly.
M3 - Journal article
C2 - 11408581
VL - 12
SP - 1737
EP - 1749
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
SN - 1059-1524
IS - 6
ER -
ID: 174222