Fig. 7
From: Phosphorylation of Arabidopsis SINA2 by CDKG1 affects its ubiquitin ligase activity
CDKG1 phosphorylates SINA2 and regulates its E3 ubiquitin ligase activity. a Recombinant SINA2 reacts strongly with anti phos Ser/Thr antibody in immunoblot assays. Reactivity was strongly reduced after in vitro dephosphorylation of recombinant SINA2 with λ protein phosphatase and increased after treatment, in vitro, with MBP-CDKG1. Dephosphorylated SINA2 was phosphorylated at Ser/Thr sites by MBP-CDKG1 but not by MBP in vitro. Immunoblots were probed with anti-His and anti–MBP as loading controls. b Increased E3 ubiquitin ligase activity of SINA2 phosphorylated by CDKG1 is indicated by enhanced accumulation of high molecular weight ubiquitinated forms in auto-ubiquitination assays. Dephosphorylated SINA2 shows reduced auto-ubiquitination activity that can be rescued by CDKG1-dependent phosphorylation