Figure 4.

Mobility Shift of TRAB1 on SDS-PAGE Caused by ABA-Induced Phosphorylation.

(A) Nuclear extracts of rice suspension-cultured cells (Oc cells) treated with ABA for the indicated times (0 indicates untreated cells) were analyzed by immunoblotting with anti-TRAB1 antibody. The arrow and asterisks indicate TRAB1-specific and nonspecific bands, respectively. Although the expression of the nonspecific bands was affected by ABA, the nature of these polypeptides is unknown.

(B) TRAB1-dHA/His expressed in transgenic cells treated without (−) or with (+) ABA for 30 min was recovered with nickel–nitrilotriacetic acid agarose resin, incubated without (−) or with (+) CIAP, and analyzed by immunoblotting with anti-HA antibody. The signals seen at the top of the +CIAP lanes are parts of bulky CIAP bands that reacted nonspecifically with the anti-HA antibody.