TY - JOUR
T1 - Dynamic reorganization of chemokine receptors, cholesterol, lipid rafts, and adhesion molecules to sites of CD4 engagement
AU - Nguyen, Dzung H.
AU - Giri, Banabihari
AU - Collins, Gary
AU - Taub, Dennis D.
PY - 2005/4/1
Y1 - 2005/4/1
N2 - T cell polarization and redistribution of cellular components are critical to processes such as activation, migration, and potentially HIV infection. Here, we investigate the effects of CD4 engagement on the redistribution and localization of chemokine receptors, CXCR4 and CCR5, adhesion molecules, and lipid raft components including cholesterol, GM1, and glycosyl- phosphatidylinositol (GPI)-anchored proteins. We demonstrate that anti-CD4-coated beads (αCD4-B) rapidly induce co-capping of chemokine receptors as well as GPI-anchored proteins and adhesion molecules with membrane cholesterol and lipid rafts on human T cell lines and primary T cells to the area of bead-cell contact. This process was dependent on the presence of cellular cholesterol, cytoskeletal reorganization, and lck signaling. Lck-deficient JCaM 1.6 cells failed to cap CXCR4 or lipid rafts to αCD4-B. Biochemical analysis reveals that CXCR4 and LFA-1 are recruited to lipid rafts upon CD4 but not CD45 engagement. Furthermore, we also demonstrate T cell capping of both lipid rafts and chemokine receptors at sites of contact with HIV-infected cells, despite the binding of an HIV inhibitory mAb to CXCR4. We conclude that cell surface rearrangements in response to CD4 engagement may serve as a means to enhance cell-to-cell signaling at the immunological synapse and modulate chemokine responsiveness, as well as facilitate HIV entry and expansion by synaptic transmission.
AB - T cell polarization and redistribution of cellular components are critical to processes such as activation, migration, and potentially HIV infection. Here, we investigate the effects of CD4 engagement on the redistribution and localization of chemokine receptors, CXCR4 and CCR5, adhesion molecules, and lipid raft components including cholesterol, GM1, and glycosyl- phosphatidylinositol (GPI)-anchored proteins. We demonstrate that anti-CD4-coated beads (αCD4-B) rapidly induce co-capping of chemokine receptors as well as GPI-anchored proteins and adhesion molecules with membrane cholesterol and lipid rafts on human T cell lines and primary T cells to the area of bead-cell contact. This process was dependent on the presence of cellular cholesterol, cytoskeletal reorganization, and lck signaling. Lck-deficient JCaM 1.6 cells failed to cap CXCR4 or lipid rafts to αCD4-B. Biochemical analysis reveals that CXCR4 and LFA-1 are recruited to lipid rafts upon CD4 but not CD45 engagement. Furthermore, we also demonstrate T cell capping of both lipid rafts and chemokine receptors at sites of contact with HIV-infected cells, despite the binding of an HIV inhibitory mAb to CXCR4. We conclude that cell surface rearrangements in response to CD4 engagement may serve as a means to enhance cell-to-cell signaling at the immunological synapse and modulate chemokine responsiveness, as well as facilitate HIV entry and expansion by synaptic transmission.
KW - CD4
KW - Chemokine receptor
KW - Cholesterol
KW - HIV
KW - Lipid rafts
UR - http://www.scopus.com/inward/record.url?scp=14644444219&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14644444219&partnerID=8YFLogxK
U2 - 10.1016/j.yexcr.2004.11.022
DO - 10.1016/j.yexcr.2004.11.022
M3 - Article
C2 - 15748900
AN - SCOPUS:14644444219
SN - 0014-4827
VL - 304
SP - 559
EP - 569
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 2
ER -