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- Title
Proteomic-Based Identification of CD4-Interacting Proteins in Human Primary Macrophages.
- Authors
Raposo, Rui André Saraiva; Thomas, Benjamin; Ridlova, Gabriela; James, William
- Abstract
Background: Human macrophages (Mϕ) express low levels of CD4 glycoprotein, which is constitutively recycled, and 40- 50% of its localization is intracellular at steady-state. Although CD4-interacting proteins in lymphoid cells are well characterised, little is known about the CD4 protein interaction-network in human Mϕ, which notably lack LCK, a Src family protein tyrosine kinase believed to stabilise CD4 at the surface of T cells. As CD4 is the main cellular receptor used by HIV-1, knowledge of its molecular interactions is important for the understanding of viral infection strategies. Methodology/Principal Findings: We performed large-scale anti-CD4 immunoprecipitations in human primary Mϕ followed by high-resolution mass spectrometry analysis to elucidate the protein interaction-network involved in induced CD4 internalization and degradation. Proteomic analysis of CD4 co-immunoisolates in resting Mϕ showed CD4 association with a range of proteins found in the cellular cortex, membrane rafts and components of clathrin-adaptor proteins, whereas in induced internalization and degradation CD4 is associated with components of specific signal transduction, transport and the proteasome. Conclusions/Significance: This is the first time that the anti-CD4 co-immunoprecipitation sub-proteome has been analysed in human primary Mϕ. Our data have identified important Mϕ cell surface CD4-interacting proteins, as well as regulatory proteins involved in internalization and degradation. The data give valuable insights into the molecular pathways involved in the regulation of CD4 expression in Mw and provide candidates/targets for further biochemical studies.
- Subjects
PROTEOMICS; CD antigens; MACROPHAGES; CELL communication; PROTEIN-tyrosine kinases; T cells; MASS spectrometry; PROTEIN-protein interactions; MICROBIAL genetics
- Publication
PLoS ONE, 2011, Vol 6, Issue 4, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0018690