Aggregation of the chemokine MIP-1 alpha is a dynamic and reversible phenomenon. Biochemical and biological analyses

J Biol Chem. 1994 Feb 18;269(7):4974-8.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Differentiation / drug effects
  • Chemokine CCL4
  • Colony-Forming Units Assay
  • Cytokines / biosynthesis*
  • Cytokines / isolation & purification
  • Cytokines / pharmacology
  • DNA Primers
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / drug effects
  • Humans
  • Macromolecular Substances
  • Macrophage Inflammatory Proteins
  • Molecular Sequence Data
  • Molecular Weight
  • Monocytes / cytology
  • Monocytes / drug effects
  • Monokines / biosynthesis*
  • Monokines / isolation & purification
  • Monokines / pharmacology
  • Mutagenesis, Site-Directed
  • Polymerase Chain Reaction
  • Protein Processing, Post-Translational*
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / pharmacology
  • Structure-Activity Relationship


  • Chemokine CCL4
  • Cytokines
  • DNA Primers
  • Macromolecular Substances
  • Macrophage Inflammatory Proteins
  • Monokines
  • Recombinant Proteins