MHC class I-hormone receptor associations: still a physiological enigma?
Besides the important role of the Major Histocompatibility Complex (MHC) class I molecules n physiologically restricting immune responses, they seem to play a non-immunological function by the molecular association with several hormone receptors (R). Among the hormone R and class I antigen (Ag) interactions, insulin R, epidermal growth factor (EGF) R, interleukin-2 (IL-2) R, luteinizing (LH) hormone R, beta adrenergic R and muscarinic cholinergic R were described in several human and animal models. Evidences from immunoprecipitation assays, binding assays and immunofluorescence techniques pointed to the molecular association of all of these R with class I molecules on cellular surfaces. Only for beta adrenergic R, muscarinic cholinergic R and LH-R, antibodies directed against class I products were described to exert the activation of these R leading to the production of intracellular second messengers and consequently modifying the physiology of the corresponding cell. This was also obtained on insulin R with peptides derived from class I molecules. The selectivity or R involved in all studied cellular types, should find its explanation in the physiological importance of the considered R for the indicated cell. The participation of cytoskeletal proteins on these interactions and the proximity on cell surfaces between both molecules, probably managed by ligand-mediated microaggregation, are also facts to be taken into account to better understand the biological consequences of these interactions.
Cremaschi
G A
GA
Centro de Estudios Farmacológicos y Botánicos (CEFYBO), CONICET, Buenos Aires, Argentina.
Sterin-Borda
L
L
D000818:Animals; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000502:physiology; D005805:Genes, MHC Class I / Q000502:physiology*; D006801:Humans; D051379:Mice; D051381:Rats; D011972:Receptor, Insulin / Q000737:chemistry / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000737:chemistry / Q000502:physiology; D015375:Receptors, Interleukin-2 / Q000737:chemistry / Q000502:physiology; D011974:Receptors, LH / Q000737:chemistry / Q000502:physiology; D011976:Receptors, Muscarinic / Q000737:chemistry / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000737:chemistry / Q000502:physiology
D011943:Receptors, Adrenergic, beta; D015375:Receptors, Interleukin-2; D011974:Receptors, LH; D011976:Receptors, Muscarinic; D017981:Receptors, Neurotransmitter; D004815:Epidermal Growth Factor; D011972:Receptor, Insulin