Fig. 2

Cleavage of APP in cultured cells by matriptase. a The APP695-EGFP (lanes 1, 3, 5, and 7) or the APP-R601A-EGFP mutant plasmid (R601A, lanes 2, 4, 6, and 8) (0.6 µg for each per transfection) was co-transfected in HEK293 cells with an empty plasmid (pLVX-Puro) (Vec, lanes 1 and 2), or the cDNA coding for human matriptase (Mat, lanes 3 and 4), protease-dead matriptase (MatM, lanes 5 and 6), or mouse TMPRSS6 (lanes 7 and 8) (0.4 µg for each per transfection). Twenty micrograms of total cell lysate from each sample were resolved on SDS-PAGE and western-blotted with an EGFP antibody or a β-tubulin antibody. The 55-kDa matriptase-specific APP-EGFP CTF is marked by the red asterisk, and the 38-kDa matriptase-specific APP-EGFP CTF is marked by the red arrowhead. b An empty plasmid (pLVX-Puro) (Vec, lane 1), or the cDNA coding for human matriptase (Mat, lane 2) or protease-dead matriptase (MatM, lane 3) (1.5 µg for each per transfection) was transfected in M17 human neuroblastoma cells. Twenty micrograms of total cell lysate from each sample were resolved on SDS-PAGE and western-blotted with an APP antibody, a matriptase antibody, or a GAPDH antibody. The data shown here were representative from three independently repeated experiments