Microtubule-associated proteins 1 (MAP1) promote human immunodeficiency virus type I (HIV-1) intracytoplasmic routing to the nucleus

J Biol Chem. 2015 Feb 20;290(8):4631-4646. doi: 10.1074/jbc.M114.613133. Epub 2014 Dec 11.

Abstract

After cell entry, HIV undergoes rapid transport toward the nucleus using microtubules and microfilaments. Neither the cellular cytoplasmic components nor the viral proteins that interact to mediate transport have yet been identified. Using a yeast two-hybrid screen, we identified four cytoskeletal components as putative interaction partners for HIV-1 p24 capsid protein: MAP1A, MAP1S, CKAP1, and WIRE. Depletion of MAP1A/MAP1S in indicator cell lines and primary human macrophages led to a profound reduction in HIV-1 infectivity as a result of impaired retrograde trafficking, demonstrated by a characteristic accumulation of capsids away from the nuclear membrane, and an overall defect in nuclear import. MAP1A/MAP1S did not impact microtubule network integrity or cell morphology but contributed to microtubule stabilization, which was shown previously to facilitate infection. In addition, we found that MAP1 proteins interact with HIV-1 cores both in vitro and in infected cells and that interaction involves MAP1 light chain LC2. Depletion of MAP1 proteins reduced the association of HIV-1 capsids with both dynamic and stable microtubules, suggesting that MAP1 proteins help tether incoming viral capsids to the microtubular network, thus promoting cytoplasmic trafficking. This work shows for the first time that following entry into target cells, HIV-1 interacts with the cytoskeleton via its p24 capsid protein. Moreover, our results support a role for MAP1 proteins in promoting efficient retrograde trafficking of HIV-1 by stimulating the formation of stable microtubules and mediating the association of HIV-1 cores with microtubules.

Keywords: Cytoskeleton; Human Immunodeficiency Virus (HIV); Microtubule; Transport; Virology.

MeSH terms

  • Active Transport, Cell Nucleus / genetics
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Line
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism*
  • Cell Nucleus / virology
  • HIV Core Protein p24 / genetics
  • HIV Core Protein p24 / metabolism
  • HIV-1 / genetics
  • HIV-1 / metabolism*
  • Humans
  • Macrophages / metabolism*
  • Macrophages / pathology
  • Macrophages / virology
  • Microfilament Proteins
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / genetics
  • Microtubules / metabolism
  • Microtubules / pathology

Substances

  • Carrier Proteins
  • HIV Core Protein p24
  • MAP1A protein, human
  • MAP1S protein, human
  • Microfilament Proteins
  • Microtubule-Associated Proteins
  • WIPF2 protein, human
  • p24 protein, Human Immunodeficiency Virus Type 1