Details

Autor(en) / Beteiligte

• Tan, Joshua H.Y.
• Canals, Meritxell
• Ludeman, Justin P.
• Wedderburn, Jamie
• Boston, Christopher
• Butler, Stephen J.
• Carrick, Ann Marie
• Parody, Todd R.
• Taleski, Deni
• Christopoulos, Arthur
• Payne, Richard J.
• Stone, Martin J.

Titel

Design and Receptor Interactions of Obligate Dimeric Mutant of Chemokine Monocyte Chemoattractant Protein-1 (MCP-1)

Ist Teil von

• The Journal of biological chemistry, 2012-04, Vol.287 (18), p.14692-14702

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• Chemokine-receptor interactions regulate leukocyte trafficking during inflammation. CC chemokines exist in equilibrium between monomeric and dimeric forms. Although the monomers can activate chemokine receptors, dimerization is required for leukocyte recruitment in vivo, and it remains controversial whether dimeric CC chemokines can bind and activate their receptors. We have developed an obligate dimeric mutant of the chemokine monocyte chemoattractant protein-1 (MCP-1) by substituting Thr10 at the dimer interface with Cys. Biophysical analysis showed that MCP-1(T10C) forms a covalent dimer with similar structure to the wild type MCP-1 dimer. Initial cell-based assays indicated that MCP-1(T10C) could activate chemokine receptor CCR2 with potency reduced 1 to 2 orders of magnitude relative to wild type MCP-1. However, analysis of size exclusion chromatography fractions demonstrated that the observed activity was due to a small proportion of MCP-1(T10C) being monomeric and highly potent, whereas the majority dimeric form could neither bind nor activate CCR2 at concentrations up to 1 μm. These observations help to reconcile previous conflicting results and indicate that dimeric CC chemokines do not bind to their receptors with affinities approaching those of the corresponding monomeric chemokines. Background: Pro-inflammatory CC chemokines form conserved dimeric structures. Results: An obligate dimeric form of MCP-1 retains the wild type dimer structure but cannot bind or activate receptor CCR2. Conclusion: CC chemokine dimers cannot bind to their receptors at affinities approaching those of the chemokine monomers. Significance: Chemokine monomer-dimer equilibria are critical in regulating leukocyte recruitment during inflammation.