Cytosol treated with GTP gamma S disintegrates lysosomes in vitro

Cytosol that was treated with guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) disintegrated lysosomes in a dose dependent manner, as detected by the release of preloaded fluorescein isothiocyanate-dextran from lysosomes. This phenomenon is a consequence of the two successive steps of incubation, (i) the treatment of cytosol with GTP gamma S, and (ii) the disintegration of lysosomes by the treated cytosol. The first step was specific for GTP gamma S and the effect of GTP gamma S was suppressed by GTP or GDP. The second step required ATP but it was not affected by bafilomycin A1. GTP gamma S treatment of lysosomes themselves did not induce their lysis. The lytic "factor(s)" produced in GTP gamma S-treated cytosol consisted of high molecular weight protein(s).