Figure 6. Detection of active matriptase in cultured primary murine keratinocytes.

Murine keratinocytes were isolated from newborn wildtype (WT) or matriptase-deficient pups (KO) and cultured on collagen-coated plastic. The cells were grown until sub-confluent and then labeled with S-NHS-SS-biotin (lanes 1, 4, 7, and 10), or with 50 µM biotin-RQRR-CMK (lanes 2, 5, 8, and 11), or with 50 µM control peptide; biotin-RQRR (lanes 3, 6, 9, and 12). Cells were lysed and analyzed on Western blot (lanes 7–12). The remaining lysates were precipitated using streptavidin-coated resin, released from the beads by boiling under non-reducing conditions and lysates were analyzed by SDS-PAGE and Western blotting using the matriptase antibody AF3946. Results shown are representative of 2 independent experiments.