Skip to main content
. 2006 Jan 30;103(6):1988–1993. doi: 10.1073/pnas.0505667103

Fig. 2.

Fig. 2.

Properties of AREB1 protein fragment phosphorylation. (A) Effects of protein kinase inhibitor staurosporine on phosphorylation of the recombinant AREB1a polypeptide. Staurosporine (20 and 100 nM) was added to reaction mixture. (B) Effects of BAPTA on phosphorylation of the recombinant AREB1b polypeptide. Na-BAPTA (5 mM final concentration) was added to reaction buffer and equilibrated for 30 min before addition of radiolabeled ATP. In the far right lane, additional kinase activity appeared near 60 kDa (see Results for details). (C) Stress-dependent phosphorylation of the recombinant AREB1b polypeptide. Protein extracts prepared from T87 cells treated for 30 min with 50 μM ABA (Ab), 0.5 M NaCl (Na), and 0.8 M mannitol (Os, high osmolality) and at low temperature (Lt, 4°C) or untreated (Ct) were used for in-gel kinase activity assay. The recombinant AREB1b polypeptide was used as a substrate. (D) ABA-activated SnRK2-type protein kinases phosphorylate the recombinant AREB1b polypeptide. Protein extracts prepared from transgenic T87 cells overexpressing each SnRK2-GFP fusion protein under control of the CaMV 35S promoter were used for in-gel kinase activity assay. Phosphorylated bands derived from SnRK2-GFP fusion proteins were indicated by circles. Arrowheads indicate the position of 42 kDa in A–D.