Supplemental Figure S1.

Syndecan-1 (Sdc1) is constitutively shed from A549 cells. A: Dot blot of conditioned medium from A549 cells demonstrates constitute shedding of syndecan-1. A549 cells were washed and fresh medium was added. After 2 and 24 hours, conditioned medium was collected and the respectively labeled microliters were added to the well of a dot-blot apparatus. Membranes were processed for dot blot using a mouse anti-human syndecan-1 antibody (MI15; BD Biosciences, San Jose, CA). B: Syndecan-1 immunofluorescence on A549 cells reveals persistent presence on the cell surface despite constitutive shedding. A549 cells were plated on chamber slides and processed for syndecan-1 immunostaining using a mouse anti-human syndecan-1 antibody (MI15) followed by an Alexa Fluor 488–conjugated anti-mouse IgG. Scale bar = 20 μm.