A possible role of carbohydrate moieties in prostaglandin D2 and prostaglandin E2 receptor proteins from the porcine temporal cortex.
The binding activities of prostaglandins (PGs) D2 and E2 were measured after deglycosylation of P2 membranes prepared from the porcine temporal cortex in order to investigate the role of carbohydrate moieties in the receptor binding. PGD2 and PGE2 binding activities were significantly decreased by pretreatment with various exoglycosidases, such as neuraminidase for PGE2 binding, alpha-mannosidase and beta-galactosidase for PGD2 binding, and beta-N-acetylhexosaminidase for both. Further, peptide N-glycohydrolase F and endo-alpha-N-acetylgalactosaminidase, which are specific for the cleavage of N-glycan and O-glycan linkages, respectively, in glycoproteins were used. Pretreatment with either of them also reduced both PGD2 and PGE2 binding activities. The reduction was dependent on the pretreatment time and enzyme concentration. The time courses of the reduction were typically characterized by a marked increase in the nonspecific bindings. Scatchard plot analysis revealed that the reduction was caused by a decrease in the affinity rather than one in the maximal binding capacity. The specificity of the binding sites thereby shifted to be more nonspecific without affecting the order of the relative affinities among PGs for the binding sites. These results suggest that the carbohydrate moieties on PG receptor proteins of the brain are essential for the expression of their binding activities.
Morii
H
H
Department of Neuroscience, Osaka Bioscience Institute, Japan.
Watanabe
Y
Y
D000581:Amidohydrolases / Q000378:metabolism; D000818:Animals; D002540:Cerebral Cortex / Q000737:chemistry*; D006031:Glycosylation; D006596:Hexosaminidases / Q000378:metabolism; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D015230:Prostaglandin D2 / Q000378:metabolism*; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D018078:Receptors, Prostaglandin E; D011983:Receptors, Purinergic / Q000737:chemistry; D013379:Substrate Specificity; D013552:Swine; D048809:alpha-N-Acetylgalactosaminidase
D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; D018078:Receptors, Prostaglandin E; D011983:Receptors, Purinergic; D006596:Hexosaminidases; D048809:alpha-N-Acetylgalactosaminidase; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D015230:Prostaglandin D2; C036293:prostaglandin D2 receptor