Jurkat cells were incubated for 1 hour without (-) or with (+) 10 μM SB 203580 and/or 2 μM PD 184352, then left untreated (-) or exposed (+) for 15 mins to HOS [0.5M sorbitol] (lower panel). CapZIP was immunoprecipitated from the cell extract using 1 μg anti- CapZIP (S970A) per 0.5 mg of extract. The immunoprecipitate was denatured in SDS, subjected to SDS/PAGE and transferred to nitrocellulose membranes. The membranes were immunoblotted with an antibody that recognises CapZIP phosphorylated at Ser 108 (anti-CapZIP phospho Ser 108 S683A) and with an antibody that recognises the phosphorylated and unphosphorylated forms of CapZIP equally well (anti-CapZIP S970A). Binding of the primary antibody was detected using rabbit peroxidase conjugated anti- sheep IgG antibody (1 in 10, 000 dilution, Pierce) followed by enhanced chemiluminescence (ECL, Amersham).