title: Plectin regulates the signaling and trafficking of the HIV-1 co-receptor CXCR4 and plays a role in HIV-1 infection.
abstract: The CXC chemokine CXCL12 and its cognate receptor CXCR4 play an important role in inflammation, human immunodeficiency virus (HIV) infection and cancer metastasis. The signal transduction and intracellular trafficking of CXCR4 are involved in these functions, but the underlying mechanisms remain incompletely understood. In the present study, we demonstrated that the CXCR4 formed a complex with the cytolinker protein plectin in a ligand-dependent manner in HEK293 cells stably expressing CXCR4. The glutathione-S-transferase (GST)-CXCR4 C-terminal fusion proteins co-precipitated with the full-length and the N-terminal fragments of plectin isoform 1 but not with the N-terminal deletion mutants of plectin isoform 1, thereby suggesting an interaction between the N-terminus of plectin and the C-terminus of CXCR4. This interaction was confirmed by confocal microscopic reconstructions showing co-distribution of these two proteins in the internal vesicles after ligand-induced internalization of CXCR4 in HEK293 cells stably expressing CXCR4. Knockdown of plectin with RNA interference (RNAi) significantly inhibited ligand-dependent CXCR4 internalization and attenuated CXCR4-mediated intracellular calcium mobilization and activation of extracellular signal regulated kinase 1/2 (ERK1/2). CXCL12-induced chemotaxis of HEK293 cells stably expressing CXCR4 and of Jurkat T cells was inhibited by the plectin RNAi. Moreover, CXCR4 tropic HIV-1 infection in MAGI (HeLa-CD4-LTR-Gal) cells was inhibited by the RNAi of plectin. Thus, plectin appears to interact with CXCR4 and plays an important role in CXCR4 signaling and trafficking and HIV-1 infection.
authors.affiliation: Department of Veterans Affairs, Nashville, TN 37212, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Ding
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: J Shawn
authors.initials: JS
authors.lastname: Goodwin
authors.forename: Ziqing
authors.initials: Z
authors.lastname: Wang
authors.forename: Bingdong
authors.initials: B
authors.lastname: Liu
authors.forename: Jingwu
authors.initials: J
authors.lastname: Zhang
authors.forename: Guo-Huang
authors.initials: GH
authors.lastname: Fan
mesh_terms: D020013:Calcium Signaling / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000276:immunology / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D004705:Endocytosis / Q000235:genetics / Q000276:immunology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000276:immunology / Q000378:metabolism; D015658:HIV Infections / Q000276:immunology* / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D046911:Macromolecular Substances / Q000378:metabolism; D018613:Microscopy, Confocal; D051190:Plectin / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000276:immunology; D034622:RNA Interference / Q000276:immunology; D019718:Receptors, CXCR4 / Q000276:immunology* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D022161:Transport Vesicles / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D053586:Virus Internalization
chemical_list: C515255:CXCL12 protein, human; C527276:CXCR4 protein, human; D054377:Chemokine CXCL12; D046911:Macromolecular Substances; D051190:Plectin; D019718:Receptors, CXCR4; D011993:Recombinant Fusion Proteins; D048049:Extracellular Signal-Regulated MAP Kinases