Aggregation of the chemokine MIP-1 alpha is a dynamic and reversible phenomenon. Biochemical and biological analyses
| Autor: | Gerard Graham, MacKenzie J, Lowe S, Ml, Tsang, Ja, Weatherbee, Issacson A, Medicherla J, Fang F, Pc, Wilkinson, Ib, Pragnell |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Base Sequence
Macromolecular Substances Monokines Molecular Sequence Data Cell Differentiation Macrophage Inflammatory Proteins Hematopoietic Stem Cells Polymerase Chain Reaction Monocytes Recombinant Proteins Colony-Forming Units Assay Molecular Weight Structure-Activity Relationship Mutagenesis Site-Directed Cytokines Humans Amino Acid Sequence Chemokine CCL4 Protein Processing Post-Translational DNA Primers |
| Zdroj: | Europe PubMed Central |
| ISSN: | 0021-9258 |
| Popis: | Macrophage inhibitory protein (MIP)-1 alpha is a potent inhibitor of hemopoietic stem cell proliferation and is a member of a family of pro-inflammatory mediators, the chemokine family. This molecule along with other members of the chemokine family exists as a peptide of 8 kDa but has a strong tendency for noncovalent extensive self-aggregation. As this aggregation may interfere with biological activity, we have produced nonaggregating variants of MIP-1 alpha which display a range of molecular sizes. The mutants, produced by sequential neutralization of carboxyl-terminal acidic residues, display native molecular masses representative of tetramers, dimers, and monomers. Intriguingly when these mutants are assessed in comparison with native MIP-1 alpha for bioactivity in vitro, they are seen to be equipotent in both stem cell assays and in monocyte shape-change assays, suggesting that there is no requirement for aggregation in either of these biological contexts. This indicates that the aggregated MIP-1 alpha and the aggregated mutants spontaneously disaggregate under assay conditions and ultimately function as monomers. We have further demonstrated the ability of MIP-1 alpha to disaggregate spontaneously in dilute solution by enzyme-linked immunosorbent assay analysis of fractions obtained from gel filtration of varying concentrations of MIP-1 alpha. The aggregation of MIP-1 alpha is therefore a dynamic and reversible phenomenon which has little, if any, impact on bioactivity in vitro. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|