Integrin modulating factor-1: a lipid that alters the function of leukocyte integrins.
The avidity of integrin CR3 (also known as alpha M beta 2, Mac-1, Mo-1, and CD11b/CD18) may be reversibly altered without changes in the number of cell surface receptors. Here we describe a molecule termed integrin modulating factor (IMF-1), which controls CR3 avidity. Addition of IMF-1 to polymorphonuclear leukocytes (PMNs) or to purified CR3 causes enhanced binding of ligand. IMF-1 is not present in resting PMNs, but stimulation of cells results in a transient rise in IMF-1 content that parallels a transient rise in CR3 activity. We suggest that PMNs control adhesivity by controlling synthesis of IMF-1, which then acts as an allosteric activator of leukocyte integrins. IMF-1 is an acidic, amphiphilic molecule of Mr340 +/- 16 that does not contain ester, phosphate, amide, sialic acid, or glycosidic or vicinal hydroxyl functionalities, but does contain a carbon-carbon double bond. These results suggest that IMF-1 is an unsaturated fatty acid or an isoprenoid acid.
Hermanowski-Vosatka
A
A
Rockefeller University, New York, New York 10021.
Van Strijp
J A
JA
Swiggard
W J
WJ
Wright
S D
SD
D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D005227:Fatty Acids / Q000737:chemistry / Q000502:physiology*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000502:physiology*; D005434:Flow Cytometry; D007700:Kinetics; D016177:Macrophage-1 Antigen / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D016177:Macrophage-1 Antigen; C072521:integrin modulating factor 1; D013755:Tetradecanoylphorbol Acetate