Fig. 7.

Glycosylation of extreme C-terminal closely spaced sites. (A) The C-terminal segment of sex hormone binding globulin (SHBG) and glycosylation site mutants. The asterisk designates the C-terminus. HeLa cells that were untreated (B) or treated with negative control (NC) siRNA or siRNAs specific for STT3A or STT3B for 48 hours (C) were transfected with SHBG expression vectors and radiolabeled 24 hours later using a 4 minute pulse label followed by a 20 minute chase. SHBG glycoforms (0–2 glycans) were immunoprecipitated with anti-SHBG and resolved by SDS-PAGE. EH designates digestion with endoglycosidase H. Quantified values below gel lanes are for the displayed image that is representative of two or more experiments.