Caveolin-1 Knockout Mice Have Altered Serum N-glycan Profile and Sialyltransferase Tissue Expression

Caveolin-1 (Cav-1) is a constitutive protein within caveolar membranes. Previous studies from our group and others indicated that Cav-1 could mediate N -glycosylation, α2,6-sialylation, and fucosylation in mouse hepatocarcinoma cells in vitro. However, little is known about the effect of Cav-1 expression on glycosylation modifications in vivo. In this study, the N -glycan profiles in serum from Cav-1 −/− mice were investigated by lectin microarray and mass spectrometric analysis approaches. The results showed that levels of multi-antennary branched, α2,6-sialylated, and galactosylated N -glycans increased, while high-mannose typed and fucosylated N -glycans decreased in the serum of Cav-1 −/− mice, compared with that of wild-type mice. Furthermore, the real-time quantitative PCR analysis indicated that α2,6-sialyltransferase gene expression decreased significantly in Cav-1 −/− mouse organ tissues, but α2,3- and α2,8-sialyltransferase did not. Of them, both mRNA and protein expression levels of the β-galactoside α2,6-sialyltransferase 1 (ST6Gal-I) had dramatically reduced in Cav-1 −/− mice organ tissues, which was consistent with the α2,6-sialyl Gal/GalNAc level reduced significantly in tissues instead of serum from Cav-1 −/− mice. These results provide for the first time the N -glycans profile of Cav-1 −/− mice serum, which will facilitate understanding the function of Cav-1 from the perspective of glycosylation.