Comparative binding of neurotrophins (NT-3, CNTF and NGF) and various cytokines to alpha 2-macroglobulin.
All the nine common cytokines in this study (including NT-3, IGF-1, CNTF and TGF-alpha) bind noncovalently, yet with different specificities and to different degrees, with both normal alpha 2-macroglobulins (alpha 2M) and monoamine-modified alpha 2M. The binding of NGF is by far the most efficient and is least affected by cationic proteins. The binding of NT-3 is slightly affected by cationic proteins but is completely blocked by NGF. The binding of TGF-alpha, TGF-beta 1, CNTF, and IL-6 is severely blocked by cationic proteins/NGF. We conclude that NGF and NT-3 appear to bind specifically in significant quantities to the same alpha 2M sites; but the other cytokines by comparison bind minimally, and primarily or entirely use nonspecific molecular interactions in their binding to alpha 2M.
Liebl
D J
DJ
Department of Microbiology and Immunology Northeastern Ohio Universities College of Medicine, Rootstown 44272.
Koo
P H
PH
D000818:Animals; D020934:Ciliary Neurotrophic Factor; D016207:Cytokines / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008297:Male; D051379:Mice; D009414:Nerve Growth Factors / Q000302:isolation & purification / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D013363:Submandibular Gland / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000302:isolation & purification / Q000378:metabolism*
D020934:Ciliary Neurotrophic Factor; D016207:Cytokines; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D000511:alpha-Macroglobulins; D012701:Serotonin