Dataset Information

The C terminus of mouse monocyte chemoattractant protein 1 (MCP1) mediates MCP1 dimerization while blocking its chemotactic potency.

ABSTRACT: The extracellular protease plasmin cleaves mouse MCP1 (monocyte chemoattractant protein 1) at lysine 104, releasing a 50-amino acid C-terminal domain. The cleavage event increases the chemotactic activity of MCP1 and, by doing so, promotes the progression of excitotoxic injury in the central nervous system in pathological settings. The mechanism through which the cleavage event enhances MCP1-mediated chemoattraction is unknown; to investigate it, we use wild-type and mutant forms of recombinant MCP1. Full-length MCP1 (FL-MCP1) is secreted by cells as a dimer or multimer. We show that a mutant truncated at the C terminus, K104Stop-MCP1, does not dimerize, revealing that the C terminus mediates the interaction. MCP1 interacts with the monocyte/microglia receptor CCR2. The interaction is critical to the function of MCP1 because CCR2(-/-) microglia do not undergo chemotaxis in response to MCP1 stimulation. We show that stimulation of microglia with FL-MCP1 or K104Stop-MCP1 triggers CCR2 internalization, whereas a mutant form unable to be cleaved at lysine 104 (K104A-MCP1) is relatively ineffective in this assay, suggesting that the C-terminal region interferes with the MCP1-CCR2 interaction. Moreover, FL-MCP1 and K104Stop-MCP1 stimulation leads to activation of Rac1, a small GTPase involved in cell migration. Conversely, MCP1-stimulated microglial migration is blocked by the Rac1 inhibitor, NSC23766, demonstrating the requirement for Rac1 effector pathways in this response. Taken together, we propose a model for MCP1 localization, activation, and function based on the initial presence and then removal of its C terminus, coupled with a requisite downstream signaling pathway from CCR2 stimulation to Rac1 activation.

SUBMITTER: Yao Y

PROVIDER: S-EPMC2951225 | biostudies-other | 2010 Oct

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

The C terminus of mouse monocyte chemoattractant protein 1 (MCP1) mediates MCP1 dimerization while blocking its chemotactic potency.

Yao Yao Y Tsirka Stella E SE

The Journal of biological chemistry 20100803 41

The extracellular protease plasmin cleaves mouse MCP1 (monocyte chemoattractant protein 1) at lysine 104, releasing a 50-amino acid C-terminal domain. The cleavage event increases the chemotactic activity of MCP1 and, by doing so, promotes the progression of excitotoxic injury in the central nervous system in pathological settings. The mechanism through which the cleavage event enhances MCP1-mediated chemoattraction is unknown; to investigate it, we use wild-type and mutant forms of recombinant ...[more]

PMID: 20682771

Similar Datasets

Project description:BackgroundEmerging evidence suggests that non-olfactory tissues and cells can express olfactory receptors (ORs), however, the exact function of ectopic OR expression remains unknown. We have previously shown in mouse models that a unique cooperation between interferon-? (IFN-?) and lipopolysaccharide (LPS) drives the activation of pulmonary macrophages and leads to the induction of pathogenic responses in the respiratory tract. Further, through gene array studies, we have shown that activation of macrophages by these molecules results in the selective expression of a number of ORs. In this study, we validated the expression of these ORs in mouse airway and pulmonary macrophages in response to IFN-? and LPS (?/LPS) stimulation, and further explored the effect of odorant stimulation on macrophage function.Methodology/principal findingsOR expression in airway and pulmonary macrophages in response to IFN-?, LPS or ?/LPS treatments was assessed by microarray and validated by q-PCR. OR expression (e.g. OR622) on macrophages was confirmed by visualization in immunofluoresence assays. Functional responses to odorants were assessed by quantifying inflammatory cytokine and chemokine expression using q-PCR and cell migration was assessed by a modified Boyden chamber migration assay. Our results demonstrate that eight ORs are expressed at basal levels in both airway and pulmonary macrophages, and that ?/LPS stimulation cooperatively increased this expression. Pulmonary macrophages exposed to the combined treatment of ?/LPS+octanal (an odorant) exhibited a 3-fold increase in MCP-1 protein production, compared to cells treated with ?/LPS alone. Supernatants from ?/LPS+octanal exposed macrophages also increased macrophage migration in vitro.Conclusions/significanceEight different ORs are expressed at basal levels in pulmonary macrophages and expression is upregulated by the synergistic action of ?/LPS. Octanal stimulation further increased MCP-1 production and the motility of macrophages. Our results suggest that ORs may mediate macrophage function by regulating MCP-1 production and cell migration.

Dataset Information

The C terminus of mouse monocyte chemoattractant protein 1 (MCP1) mediates MCP1 dimerization while blocking its chemotactic potency.

Publications

The C terminus of mouse monocyte chemoattractant protein 1 (MCP1) mediates MCP1 dimerization while blocking its chemotactic potency.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets