Figure 7.

Identification of receptor for γ2 short arm. (A) Surface membrane proteins of EJ-1 cells were biotinylated with Biotin-OSu (Dojindo, Kumamoto, Japan), and the labeled proteins were passed through a γ2sa-conjugated column (γ2sa) or a control column without γ2sa (Cont.). Bound materials were eluted with 1 M NaCl, separated by nonreducing SDS-PAGE on a 5–12% gradient gel, and electrotransferred to a nitrocellulose membrane. The transferred membrane proteins were detected with the horseradish peroxidese-avidin D/ECL method. The arrow indicates molecules specifically bound to the γ2sa column. (B) The labeled membrane proteins were passed through columns conjugated with 0, 0.25, or 1.0 μg/ml γ2sa in the absence (−) or presence (+) of 1.0 μg/ml heparin. Bound materials were eluted from the column, treated with heparitinase, and immunoblotted with an anti-Δheparan sulfate antibody (top) and an anti-syndecan-1 antibody (bottom). Arrowheads, syndecan-1 core proteins and their apparent molecular sizes in kilodaltons.