6z1c
From Proteopedia
Crystal structure of Arabidopsis thaliana CK2-alpha-1 in complex with TTP-22
Structural highlights
Function[CSK21_ARATH] Casein kinases are operationally defined by their preferential utilization of acidic proteins such as caseins as substrates. Phosphorylates casein in vitro (PubMed:7678767). The alpha chain contains the catalytic site. The tetrameric holoenzyme CK2, composed of two alpha and two beta subunits, phosphorylates the transcription factor GBFl, resulting in stimulation of its DNA binding activity (PubMed:7696877). CK2 phosphorylates the transcription factor PIF1 after an exposure to light, resulting in a proteasome-dependent degradation of PIF1 and promotion of photomorphogenesis (PubMed:21330376). CK2 phosphorylates translation initiation factors. May participate in the regulation of the initiation of translation (PubMed:19509278, PubMed:19509420). Acts as circadian clock component that maintains the correct period length through phosphorylation of CCA1 (PubMed:21900482). Required for the maintenance and control of genomic stability and chromatin structure (PubMed:22487192). May act as an ectokinase that phosphorylates several extracellular proteins.[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedAluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses strongly inhibit root growth, resulting from a progressive exhaustion of the stem cell niche. Here, we report on a casein kinase 2 (CK2) inhibitor identified by its capability to maintain a functional root stem cell niche in Arabidopsis thaliana under Al toxic conditions. CK2 operates through phosphorylation of the cell cycle checkpoint activator SUPPRESSOR OF GAMMA RADIATION1 (SOG1), priming its activity under DNA-damaging conditions. In addition to yielding Al tolerance, CK2 and SOG1 inactivation prevents meristem exhaustion under Pi starvation, revealing the existence of a low Pi-induced cell cycle checkpoint that depends on the DNA damage activator ATAXIA-TELANGIECTASIA MUTATED (ATM). Overall, our data reveal an important physiological role for the plant DNA damage response pathway under agriculturally limiting growth conditions, opening new avenues to cope with Pi limitation. Arabidopsis casein kinase 2 triggers stem cell exhaustion under Al toxicity and phosphate deficiency through activating the DNA damage response pathway.,Wei P, Demulder M, David P, Eekhout T, Yoshiyama KO, Nguyen L, Vercauteren I, Eeckhout D, Galle M, De Jaeger G, Larsen P, Audenaert D, Desnos T, Nussaume L, Loris R, De Veylder L Plant Cell. 2021 Jan 25. pii: 6119328. doi: 10.1093/plcell/koab005. PMID:33793856[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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