FIG. 7.

Phosphorylation regulates caspase cleavage of SATB1 in vivo. (A) Jurkat cells treated with calphostin C (5 μM, 30 min, 24°C, in light) and then with anti-Fas for the times indicated were collected and immediately lysed with SDS-PAGE loading buffer and then fractionated by SDS-PAGE and immunoblotted to anti-SATB1. Lane −, untreated control cells. (B) Nalm-6 cells transiently overexpressing EGFP-SATB1(FL) constructs (wild-type [wt], T188A, T188E/LXXAA, or sumoylation site mutant [K744R]) were treated with etoposide for the indicated times, harvested as described above, and examined by immunoblotting to anti-SATB1 or anti-PARP (as shown) antibody. Only the 89-kDa cleavage product of PARP (116 kDA) was detected by anti-PARP antibody.