Science Links Japan | Processing of O-linked Glycosylation in the Chimera Consisting of .ALPHA.-Subunit and Carboxyl-terminal Peptide of the Human Chorionic Gonadotropin .BETA.-Subunit is Affected by Dimer Formation with Follicle-stimulating Hormone .BETA.-Subunit

Processing of O-linked Glycosylation in the Chimera Consisting of .ALPHA.-Subunit and Carboxyl-terminal Peptide of the Human Chorionic Gonadotropin .BETA.-Subunit is Affected by Dimer Formation with Follicle-stimulating Hormone .BETA.-Subunit

Accession number;04A0170021

Title;Processing of O-linked Glycosylation in the Chimera Consisting of .ALPHA.-Subunit and Carboxyl-terminal Peptide of the Human Chorionic Gonadotropin .BETA.-Subunit is Affected by Dimer Formation with Follicle-stimulating Hormone .BETA.-Subunit

Author; FURUHASHI M (Japanese Red Cross Nagoya First Hospital, Nagoya, Jpn) SUGANUMA N (Toyohashi Municipal Hospital, Toyohashi, Jpn)

Journal Title;Endocr J

Journal Code:F0625A

ISSN:0918-8959

VOL.51;NO.1;PAGE.53-59(2004)

Figure&Table&Reference;FIG.4, REF.38

Pub. Country;Japan

Language;English

Abstract;hCG, LH, FSH, and TSH are a family of heterodimeric glycoprotein hormones that contain a common .ALPHA.-subunit, but differ in their hormone-specific .BETA.-subunits. hCG.BETA. is unique among .BETA.-subunits due to a carboxyl-terminal peptide (CTP) bearing four O-linked oligosaccharides. We previously reported that there were differences in O-glycosylation between two chimeras consisting of .ALPHA.-subunit and CTP, i.e. a variant with CTP at the N-terminal region (C.ALPHA.) and another analog with CTP at the C-terminus (.ALPHA.C) of the .ALPHA.-subunit. To address whether O-glycosylation is influenced by the heterodimer formation, C.ALPHA. and .ALPHA.C were expressed alone or with FSH.BETA.-subunit in Chinese hamster ovary cells. The O-linked glycosylation was assessed by continuous labeling with [35S]methionine/cysteine, immunoprecipitation with anti-.ALPHA. or anti-FSH serum, serial digestion with endoglycosidase-F and neuraminidase, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The decrease in molecular weight of dimeric chimeras digested with endoglycosidase-F was greater in C.ALPHA. than that in .ALPHA.C after treatment with neuraminidase, revealing that both chimeras have different numbers of sialic acids on O-linked carbohydrates. By treating with endoglycosidase-F, the dimeric .ALPHA.C migrated faster than its free form, whereas the mobility difference between assembled and unassembled forms of C.ALPHA. was very little. These data indicate that processing of O-glycosylation is affected by the backbone polypeptide chain(s). (author abst.)

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