Figure 2. The nuclear actin/HDAC 1 and 2 interaction is activity dependent.
(a) HeLa cells were treated with 4 μM TSA for 3 h and crosslinked with DSP before extraction. Extracts were prepared and immunoprecipitated with β-actin antibody and immunoblotted for β-actin, HDAC 1 and 2. Band densities were quantified in the β-actin IP lane and calculated as a ratio of HDAC 1 intensity to β-actin. Note the decrease in the association between β-actin and HDAC 1 and HDAC2 in the TSA treated cells vs. control. Mean + SEM, N = 5, *p < 0.05 by t-test. (b) Same as in (a) except extracts were immunoprecipitated with HDAC 1 antibodies and immunoblotted for β-actin, HDAC 1, and HDAC 2. Note that TSA decreases not only the interaction between β-actin and HDAC 1 and 2 as in (a), but also the interaction between HDAC 1 and HDAC 2, suggesting the entire HDAC complex is dissociated. (c) HL60 cells were left untreated (control) or treated with 50 ng/mL PMA for 72 h to induce a differentiated monocytic phenotype. Cells were then lysed, immunoprecipitated with antibodies to β-actin, then blotted with antibodies to β-actin and HDAC 1.