Figure 6

The stimulatory effect of MEKK1 on PR-B transcriptional activity is independent of the SUMO conjugation site. HeLa cells were transfected with 2 μg of PRE2-luciferase reporters together with 50 ng of wild type PR-B (A), PR-B S294/345 phosphorylation mutant (B), or PR-B K388R SUMOylation deficient mutant (C) expression vectors and Renilla-Luc as an internal control in the presence or absence of 100 ng SENP1 and/or constitutively active MEKK1 expression vectors. The cells were treated for 24 hrs with the agonist R5020 (10 nM) then harvested and lysed. The extracts were assayed for luciferase activities as in Figure 1.