O‐ and N‐glycosylation lead to different molecular mass forms of human monocyte interleukin‐6

FEBS Letters

Andus, Tilo²  Vom Berg, Daniela²  Gerok, Wolfgang²  Heinrich, Peter C.¹  Castell, José²  Gross, Volker² 

[1] Institut für Biochemie der RWTH Aachen, Pauwelsstraße, 5100 Aachen, FRG;Medizinische Universitätsklinik, Hugstetter Str. 55, 7800 Freiburg, FRG

关键词: Interleukin-6;    Glycosylation;    N-;    Glycosylation;    O-;    (Human monocyte);   

DOI  :  10.1016/0014-5793(89)81361-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The biosynthesis and secretion of human interleukin-6 (IL-6) was studied in monocyte cultures stimulated with endotoxin. After labeling with [³⁵S]methionine and immunoprecipitation with a specific antiserum one major (24 kDa) and four minor (27.5, 23.3, 22.5 and 21.8 kDa) molecular mass forms of IL-6 could be found in the cells and media. Incubation of monocyte media with sialidase and subsequently with endo-α-N-acetylgalactosaminidase, which cleaves Ga1(β1-3)Gal-NAc from serine or threonine, led to the formation of only two forms of IL-6 with apparent molecular masses of 25 and 21.8 kDa. The latter had an electrophoretic mobility indistinguishable from that of ¹²⁵I-labeled recombinant human IL-6. The results suggest that human monocyte IL-6 carries O-glycosidically bound carbohydrates with a Ga1(β1-3)Gal-NAc core to which only sialic acid is bound. Differences in O-glycosylation are the major cause for the molecular heterogeneity of IL-6. A small part of IL-6 (27.5 kDa form) is in addition N-glycosylated. Incubation of monocytes with tunicamycin and 1-deoxymynnojirimycin and treatment of IL-6 with endoglucosaminidase H suggested that the 27.5 kDa form of IL-6 carries at least one N-linked complex-type oligosaccharide chain.

【 授权许可】

Unknown