Figure 3.

Intracellular cysteine proteinase expression during MDM differentiation. Cell lysates (10 μg/lane) were harvested at 2 h, and 3, 5, 7, and 12 d, and immunoblotted with anti–cathepsin K, B, S, and L Abs. The pro- (white arrowheads) and mature (arrows) forms of the enzymes are highlighted. Mature cathepsin B is expressed as a single and two chain active form (M _r ∼31 and ∼25 kD, respectively; see reference 7). Results are shown from a single representative experiment of three performed.