Fig 3.

IreB phosphorylation state in vivo is dependent on IreK activity. Clarified lysates from exponentially growing cells were spiked with an ∼27-kDa Strep-tagged protein standard (to serve as a landmark) and subjected to isoelectric focusing (pH gradient depicted at top) followed by SDS-PAGE and immunoblotting with anti-strep antibody. The protein standard is indicated with an asterisk, and isoforms of IreB-strep are indicated with an arrow in each panel. Strains: WT, OG1RF; ΔireP, CK121. Plasmids: vector, pDL278p23; pIreB strep, pJRG39; pIreB T4A T7A strep, pJLL14.