Figure 4. Identification and role of phosphorylated serines in CRN8 cell death induction.
(A) A cartoon of the CRN8 protein (yellow) with the five phosphorylated serines identified by LC MS/MS denoted by green bars. Portion of CRN8 shown in light yellow was not represented in peptide coverage. Asterisks indicate serines that were included in the CRN8S3xA triple mutant. FLAG sequence (blue portion) and the linker sequence (orange portion) are included. (B) The top panel shows macroscopic cell death associated with A. tumefaciens-mediated transient expression of FLAG:CRN8, FLAG:CRN8D470N, FLAG:CRN8R469A;D470A, FLAG:CRN8S3xA, and FLAG:CRN8S5xA in N. benthamiana. Pictures were taken 8 days after inoculation. The middle panel shows that phosphorylated protein was detected for FLAG:CRN8, FLAG:CRN8S3xA, and FLAG:CRN8S5xA the in FLAG immuno-purified protein by Pro-Q Diamond phosphoprotein in gel stain. The bottom panel shows that all five FLAG immuno-purified fusion proteins were present, as detected by FLAG antibody on a Western blot.