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β2 Integrin Adhesion Complexes Maintain the Integrity of HIV ‐1 Assembly Compartments in Primary Macrophages
Author(s) -
PelchenMatthews Annegret,
Giese Sebastian,
Mlčochová Petra,
Turner Jane,
Marsh Mark
Publication year - 2012
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2011.01306.x
Subject(s) - microbiology and biotechnology , paxillin , biology , focal adhesion , integrin , integrin alpha m , cytoskeleton , cd18 , vinculin , adhesion , cell adhesion , actin cytoskeleton , actin , cytoplasm , intracellular , biochemistry , cell , chemistry , signal transduction , organic chemistry
In human monocyte‐derived macrophages ( MDM ), human immunodeficiency virus type 1 ( HIV ‐1) assembly takes place primarily on complex intracellular plasma membrane domains connected to the cell surface by closely apposed membrane sheets or narrow channels. Some of the membranes associated with these compartments are decorated by thick (≈30 nm ), electron‐dense, cytoplasmic coats. Here we show by immunolabelling of ultrathin cryosections that the β2 integrin CD 18, together with the α M and α X integrins ( CD 11 b and CD 11 c ), is clustered at these coated domains, and that the coats themselves contain the cytoskeletal linker proteins talin, vinculin and paxillin that connect the integrin complexes to the actin cytoskeleton. Intracellular plasma membrane‐connected compartments ( IPMC ) with CD 18‐containing focal adhesion‐like coats are also present in uninfected MDM . These compartments become more prominent as the cells mature in tissue culture and their appearance correlates with increased expression of CD 18, CD 11 b / c and paxillin. Depletion of CD 18 by RNA interference leads to parallel down‐regulation of CD 11 b and CD 11 c , as well as of paxillin, and the disappearance of the adhesion‐like coats. In addition, CD 18 knockdown alters the appearance of virus‐containing IPMC in HIV ‐infected MDM , indicating that the β2 integrin/focal adhesion‐like coat structures are involved in the organization of these compartments.