Ottersbach K, McLean J, Isaacs NW, Graham GJ. A310 helical turn is essential for the proliferation-inhibiting properties of macrophage inflammatory protein-1 alpha (CCL3).
Blood 2005;
107:1284-91. [PMID:
16234357 DOI:
10.1182/blood-2005-08-3112]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Despite possessing marked structural similarities, the chemokines macrophage inflammatory protein-1alpha (MIP-1alpha; CCL3) and RANTES (CCL5) display differential activity in hematopoietic progenitor-cell-inhibitory assays, with MIP-1alpha being active and RANTES inactive in this context. We have sought to identify the key structural determinants of this property of MIP-1alpha. This has involved constructing MIP-1alpha/RANTES chimeras by swapping structural domains between the 2 proteins. Results indicate that, in contrast to other chemokine functions, neither the N nor the C termini are key determinants of inhibitory activity. The motif that appears to be most important for this activity lies between the second and fourth cysteines of MIP-1alpha and further domain swap analysis has narrowed this down to the 3 10 helical turn preceding the first beta-strand in MIP-1alpha. More detailed analysis has highlighted the role played by a specific dipeptide motif in the proliferation-inhibitory activity of chemokines. The involvement of the 3 10 helical-turn motif in chemokine function is unprecedented and this study therefore identifies a novel, functionally essential motif within chemokines. In addition, this study further attests to the alternative mechanisms of action used by MIP-1alpha in inhibition of hematopoietic progenitor-cell proliferation and regulation of leukocyte migration.
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