Figure 2

α2–6 sialylation of β ₁ integrins in three ovarian carcinoma cell lines. A, Lysates from PA1, OV4, and SKOV3 cells were incubated with agarose-conjugated SNA, a lectin specific for α2–6 sialic acids. Glycoproteins were precipitated, resolved by SDS-PAGE and immunoblotted for the β₁ integrin. B, Cell lysates were immunoblotted for the β₁ integrin to control for total levels of protein expression. The top band in β₁ immunoblots represents the functional receptor isoform ("mature β₁"), whereas the bottom band represents a precursor, ER-resident, form of β₁. Of note, OV4 cells do not appear to express a precursor isoform.