[The role of myeloid differential protein-2 in innate immunity].
As typical PRRs (pattern-recognition receptors), TLRs (Toll-like receptors) play an important role during innate immunity recognition. MD-2 (myeloid differential protein-2) may contain distinct functional domains that can separately and simultaneously bind TLRs (TLR4 or TLR2) and TLR ligands, such as lipopolysaccharide (LPS). The special structure of MD-2 may result in its three main functions: (1) An association with TLR4 that amplifies TLR4 responsiveness to ligands, especially LPS. (2) Enabling TLR2-mediated responses to LPS and enhancing TLR2-mediated responses to bacteria and their cell wall components. (3) Increasing the expression of TLR2 and TLR4 and possibly influencing the correct intracellular distribution of TLR4. Importantly, while MD-2 regulation of TLR expression and distribution is well established, determining whether the interaction is direct or not will require further study. Thus, MD-2 is not only an assistant molecule of TLR4 but is also a key regulatory molecule in innate immunity, and may play important roles during infection, inflammation, immune responses and many other pathologic and physiologic processes.
Research Institute of Surgery, Third Military Medical University, Chongqing 400042.
Fa-Liang
FL
Xu
Lei
L
Li
D000818:Animals; D000954:Antigens, Surface / Q000502:physiology*; D002352:Carrier Proteins / Q000502:physiology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D008070:Lipopolysaccharides / Q000378:metabolism; D051218:Lymphocyte Antigen 96; D008562:Membrane Glycoproteins / Q000502:physiology*; D018375:Neutrophil Activation / Q000502:physiology; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D011956:Receptors, Cell Surface / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors
D000954:Antigens, Surface; D002352:Carrier Proteins; C495377:LY96 protein, human; D008070:Lipopolysaccharides; D051218:Lymphocyte Antigen 96; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors