FIGURE 2.

PDZ-RhoGEF/LARG is associated with the increase of ABCA1 protein levels. A, knockdown of RhoGEF expression by siRNA suppressed the apoA-I-mediated ABCA1 stabilization in primary human fibroblast. The cells were transfected with either a nontargeting pool of siRNA duplexes (negative control), siRNA duplex targeting PDZ-RhoGEF, or LARG, or a mixture of siRNA duplexes targeting both PDZ-RhoGEF and LARG. After 48 h transfection, the cells were incubated with apoA-I for 1 h. The level of ABCA1 protein was quantified using a LAS-3000 imager. B, PDZ-RhoGEF expression increased ABCA1 protein level in cells expressing wild-type (WT) ABCA1 but in cells expressing the ABCA1-Δ4 mutant, which disrupts the ABCA1 PDZ-binding motif. 293 cells were transfected with wild-type or Δ4 mutant of ABCA1 cDNA either alone or together with PDZ-RhoGEF cDNA. The results are representatives of two or more experiments.