HIV-1 Fusion with CD4+ T cells Is Promoted by Proteins Involved in Endocytosis and Intracellular Membrane Trafficking

Abstract

The HIV-1 entry pathway into permissive cells has been a subject of debate. Accumulating evidence, including our previous single virus tracking results, suggests that HIV-1 can enter different cell types via endocytosis and CD4/coreceptor-dependent fusion with endosomes. However, recent studies that employed indirect techniques to infer the sites of HIV-1 entry into CD4+ T cells have concluded that endocytosis does not contribute to infection. To assess whether HIV-1 enters these cells via endocytosis, we probed the role of intracellular trafficking in HIV-1 entry/fusion by a targeted shRNA screen in a CD4+ T cell line. We performed a screen utilizing a direct virus-cell fusion assay as readout and identified several host proteins involved in endosomal trafficking/maturation, including Rab5A and sorting nexins, as factors regulating HIV-1 fusion and infection. Knockdown of these proteins inhibited HIV-1 fusion irrespective of coreceptor tropism, without altering the CD4 or coreceptor expression, or compromising the virus’ ability to mediate fusion of two adjacent cells initiated by virus-plasma membrane fusion. Ectopic expression of Rab5A in non-permissive cells harboring Rab5A shRNAs partially restored the HIV-cell fusion. Together, these results implicate endocytic machinery in productive HIV-1 entry into CD4+ T cells.

The late endosome-resident lipid bis(monoacylglycero)phosphate is a cofactor for Lassa virus fusion

“…The HIV-1-based packaging vector pR9ΔEnv was from Dr. Chris Aiken (Vanderbilt University). The pMM310 vector expressing BlaM-Vpr, psPAX2 lentiviral packaging vector, pcRev vector, pMDG-VSVG plasmid expressing VSV-G, H1N1 WSN HA and NA expression vectors were described previously (35, 88). The pNL4-3.Luc.R-E-packaging vector was obtained through the NIH AIDS Reagent Program (from Dr. Nathaniel Landau (89)).…”

Endocytosis of abiotic nanomaterials and nanobiovectors: Inhibition of membrane trafficking

“…Viruses larger than the invaginations observed in CME or caveolae-mediated endocytosis employ preferentially this mechanism for cell entry, as observed for many filoviruses, poxviruses, paramyxovirus, adenovirus and HIV-1 [203] , [232] . One well-studied example is the filovirus Ebola ( Fig.…”

“… Virus Family Receptor Mechanism Ref. Vesicular stomatitis virus Rhabdoviridae Low-density lipoprotein receptors (LDL-R) Clathrin-mediated [189] Dengue Virus Flaviviridae GAG, DC-SIGN and other C-Type lectin receptors Clathrin-mediated [190] , [191] Influenza A virus Myxoviridae Sialic acid containing receptors Clathrin-mediated, Macropinocytosis [192] Simian Virus 40 Poliomaviridae GM1 ganglioside Caveolae-mediated [193] , [194] ZIKA virus Flaviviridae DC-SIGN and other C-type lectin receptors, TIM and TAM receptors Clathrin-mediated, Caveolae-mediated [195] , [196] Mayaro virus Alphaviridae Matrix Remodeling Associated 8 (MXRA8) Clathrin-mediated, Caveolae-mediated [197] HCoV-OC43 Betacoronaviridae Sialoglycan-based receptors Caveolae-mediated [198] African swine fever virus Asfarviridae CD163 Clathrin-mediated, Macropinocytosis [199] , [200] Ebolavirus Filoviridae DC-SIGN and other C-type lectin receptors Macropinocytosis [201] Vaccinia virus Poxviridae Heparan sulfate Proteoglycan Macropinocytosis [202] Human immunodeficiency virus-1 Retroviridae CD4 and CCR5or CXCR4 Clathrin-mediated Macropinocytosis [203] , [204] ...…”

HIV-1 Hijacking of Host ATPases and GTPases That Control Protein Trafficking

“…• Involved in endocytic entry of HIV-1 Vidricaire and Tremblay, 2005;Marin et al, 2019 Ran • HIV PIC nuclear import.…”

“…In fact, the expression of small GTPases Rab5 or Rab7 mutants, known to impair endosome maturation, also inhibited HIV-1 infection in those cells ( Vidricaire and Tremblay, 2005 ). Recently, Marin et al (2019) found that the knockdown of Rab5, Rab11A or the Rab effector protein RABEP1 decrease HIV-1 fusion with endosomes in CD4+ T cells, highlighting the importance of the endocytic machinery in the HIV-1 entry process.…”