Dataset Information

Proteomic-based identification of CD4-interacting proteins in human primary macrophages.

ABSTRACT: Human macrophages (M?) 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 M?, 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.We performed large-scale anti-CD4 immunoprecipitations in human primary M? 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 M? 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.This is the first time that the anti-CD4 co-immunoprecipitation sub-proteome has been analysed in human primary M?. Our data have identified important M? 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 M? and provide candidates/targets for further biochemical studies.

SUBMITTER: Raposo RA

PROVIDER: S-EPMC3076427 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature

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Proteomic-based identification of CD4-interacting proteins in human primary macrophages.

Raposo Rui André Saraiva RA Thomas Benjamin B Ridlova Gabriela G James William W

PloS one 20110413 4

<h4>Background</h4>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, knowle ...[more]

PMID: 21533244

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Project description:In the brain, the Homer protein family modulates excitatory signal transduction and receptor plasticity through interactions with other proteins in dendritic spines. Homer proteins are implicated in a variety of psychiatric disorders such as schizophrenia and addiction. Since long Homers serve as scaffolding proteins, identifying their interacting partners is an important first step in understanding their biological function and could help to guide the design of new therapeutic strategies. The present study set out to document Homer2-interacting proteins in the mouse brain using a co-immunoprecipitation-based mass spectrometry approach where Homer2 knockout samples were used to filter out non-specific interactors. We found that in the mouse brain, Homer2 interacts with a limited subset of its previously reported interacting partners (3 out of 31). Importantly, we detected an additional 15 novel Homer2-interacting proteins, most of which are part of the N-methyl-D-aspartate receptor signaling pathway. These results corroborate the central role Homer2 plays in glutamatergic transmission and expand the network of proteins potentially contributing to the behavioral abnormalities associated with altered Homer2 expression.SignificanceLong Homer proteins are scaffolding proteins that regulate signal transduction in neurons. Identifying their interacting partners is key to understanding their function. We used co-immunoprecipitation in combination with mass spectrometry to establish the first comprehensive list of Homer2-interacting partners in the mouse brain. The specificity of interactions was evaluated using Homer2 knockout brain tissue as a negative control. The set of proteins that we identified minimally overlaps with previously reported interacting partners of Homer2; however, we identified novel interactors that are part of a signaling cascade activated by glutamatergic transmission, which improves our mechanistic understanding of the role of Homer2 in behavior.

Dataset Information

Proteomic-based identification of CD4-interacting proteins in human primary macrophages.

Publications

Proteomic-based identification of CD4-interacting proteins in human primary macrophages.

Similar Datasets

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