5wrr
Crystal structure of Fam20A
Structural highlights
DiseaseFA20A_HUMAN Amelogenesis imperfecta - nephrocalcinosis;Amelogenesis imperfecta and gingival hyperplasia syndrome. The disease is caused by mutations affecting the gene represented in this entry. FunctionFA20A_HUMAN Pseudokinase that acts as an allosteric activator of the Golgi serine/threonine protein kinase FAM20C and is involved in biomineralization of teeth. Forms a complex with FAM20C and increases the ability of FAM20C to phosphorylate the proteins that form the 'matrix' that guides the deposition of the enamel minerals.[1] Publication Abstract from PubMedMutations in FAM20A cause tooth enamel defects known as Amelogenesis Imperfecta (AI) and renal calcification. We previously showed that Fam20A is a secretory pathway pseudokinase and allosterically activates the physiological casein kinase Fam20C to phosphorylate secreted proteins important for biomineralization (Cui et al., 2015). Here we report the nucleotide-free and ATP-bound structures of Fam20A. Fam20A exhibits a distinct disulfide bond pattern mediated by a unique insertion region. Loss of this insertion due to abnormal mRNA splicing interferes with the structure and function of Fam20A, resulting in AI. Fam20A binds ATP in the absence of divalent cations, and strikingly, ATP is bound in an inverted orientation compared to other kinases. Fam20A forms a dimer in the crystal, and residues in the dimer interface are critical for Fam20C activation. Together, these results provide structural insights into the function of Fam20A and shed light on the mechanism by which Fam20A mutations cause disease. Structure of Fam20A reveals a pseudokinase featuring a unique disulfide pattern and inverted ATP-binding.,Cui J, Zhu Q, Zhang H, Cianfrocco MA, Leschziner AE, Dixon JE, Xiao J Elife. 2017 Apr 22;6. pii: e23990. doi: 10.7554/eLife.23990. PMID:28432788[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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