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. 2013 Feb 21;9(2):e1003315. doi: 10.1371/journal.pgen.1003315

Figure 1. FOS-1 is phosphorylated by KGB-1.

Figure 1

(A) Schematic representation of the structures of human c-Fos and C. elegans FOS-1 proteins. Dark boxes represent the basic and leucine zipper regions. Six Ser/Thr-Pro motifs are shown. (B) Interaction of FOS-1 with KGB-1. COS-7 cells were co-transfected with expression vectors encoding T7-FOS-1 and HA-KGB-1(K67R; KN) as indicated. Whole cell extracts (WCE) and immunoprecipitated complexes obtained with anti-HA antibodies (IP) were analyzed by Western blot (WB). Experiments were performed five times with similar results. (C, D) Phosphorylation of FOS-1 by KGB-1. COS-7 cells were co-transfected with expression vectors encoding T7-FOS-1 (wild type; WT), T7-FOS-1(T304A), HA-KGB-1 WT, HA-KGB-1 KN, and FLAG-MEK-1 as indicated. Whole cell extracts were incubated in either the absence or presence of calf intestine alkali phosphatase (CIAP) before analyzing by Western blot (C). Experiments were performed three times with similar results. (E) FOS-1 dimerization is inhibited by KGB-1-mediated phosphorylation. COS-7 cells were co-transfected with expression vectors encoding T7-FOS-1 WT, GFP-FLAG-FOS-1 WT, HA-KGB-1 WT, HA-KGB-1 KN, and FLAG-MEK-1 as indicated. Whole cell extracts and immunoprecipitated complexes obtained with anti-GFP antibodies were analyzed by Western blot (WB). Arrowheads indicate the positions of phosphorylated GFP-FLAG-FOS-1 and T7-FOS-1. Experiments were performed three times with similar results.