4CZU

Crystal structure of the kinase domain of CIPK23 T190D mutant

Summary for 4CZU

• Entry DOI: 10.2210/pdb4czu/pdb
• Related: 4CZT 4D28
• Descriptor: CBL-INTERACTING SERINE/THREONINE-PROTEIN KINASE 23, 3-[(3-CHOLAMIDOPROPYL)DIMETHYLAMMONIO]-1-PROPANESULFONATE, SULFATE ION, ... (4 entities in total)
• Functional Keywords: transferase, potassium transport, snrk3
• Biological source: ARABIDOPSIS THALIANA (THALE CRESS)
• Total number of polymer chains: 4
• Total formula weight: 213258.65

Authors

Chaves-Sanjuan, A.,Sanchez-Barrena, M.J.,Albert, A. (deposition date: 2014-04-22, release date: 2014-10-15, Last modification date: 2024-10-23)

Primary citation

Chaves-Sanjuan, A.,Sanchez-Barrena, M.J.,Gonzalez-Rubio, J.M.,Moreno, M.,Ragel, P.,Jimenez, M.,Pardo, J.M.,Martinez-Ripoll, M.,Quintero, F.J.,Albert, A.
Structural Basis of the Regulatory Mechanism of the Plant Cipk Family of Protein Kinases Controlling Ion Homeostasis and Abiotic Stress
Proc.Natl.Acad.Sci.USA, 111:E4532-, 2014

PubMed Abstract: Plant cells have developed specific protective molecular machinery against environmental stresses. The family of CBL-interacting protein kinases (CIPK) and their interacting activators, the calcium sensors calcineurin B-like (CBLs), work together to decode calcium signals elicited by stress situations. The molecular basis of biological activation of CIPKs relies on the calcium-dependent interaction of a self-inhibitory NAF motif with a particular CBL, the phosphorylation of the activation loop by upstream kinases, and the subsequent phosphorylation of the CBL by the CIPK. We present the crystal structures of the NAF-truncated and pseudophosphorylated kinase domains of CIPK23 and CIPK24/SOS2. In addition, we provide biochemical data showing that although CIPK23 is intrinsically inactive and requires an external stimulation, CIPK24/SOS2 displays basal activity. This data correlates well with the observed conformation of the respective activation loops: Although the loop of CIPK23 is folded into a well-ordered structure that blocks the active site access to substrates, the loop of CIPK24/SOS2 protrudes out of the active site and allows catalysis. These structures together with biochemical and biophysical data show that CIPK kinase activity necessarily requires the coordinated releases of the activation loop from the active site and of the NAF motif from the nucleotide-binding site. Taken all together, we postulate the basis for a conserved calcium-dependent NAF-mediated regulation of CIPKs and a variable regulation by upstream kinases.

PubMed: 25288725
DOI: 10.1073/PNAS.1407610111

Experimental method

X-RAY DIFFRACTION (1.9 Å)