title: Gatekeeper tyrosine phosphorylation is autoinhibitory for Symbiosis Receptor Kinase.
abstract: Plant receptor-like kinases (RLKs) are distinguished by having a tyrosine in the 'gatekeeper' position. Previously we reported Symbiosis Receptor Kinase from Arachis hypogaea (AhSYMRK) to autophosphorylate on the gatekeeper tyrosine (Y670), though this phosphorylation was not necessary for the kinase activity. Here we report that recombinant catalytic domain of AhSYMRK with a phosphomimic substitution in the gatekeeper position (Y670E) is catalytically almost inactive and is conformationally quite distinct from the corresponding native enzyme. Additionally, we show that gatekeeper-phosphorylated AhSYMRK polypeptides are inactive and depletion of this inactive form leads to activation of intramolecular autophosphorylation of AhSYMRK. Together, our results suggest gatekeeper tyrosine autophosphorylation to be autoinhibitory for AhSYMRK.
authors.affiliation: Department of Biochemistry, University of Calcutta, Kolkata, India.
authors.forename: Anindita
authors.initials: A
authors.lastname: Paul
authors.affiliation: Department of Biochemistry, University of Calcutta, Kolkata, India.
authors.forename: Sandip
authors.initials: S
authors.lastname: Samaddar
authors.affiliation: Department of Biochemistry, University of Calcutta, Kolkata, India.
authors.forename: Avisek
authors.initials: A
authors.lastname: Bhattacharya
authors.affiliation: Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India.
authors.forename: Anindyajit
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Das
authors.affiliation: Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India.
authors.forename: Saikat
authors.initials: S
authors.lastname: Chakrabarti
authors.affiliation: Department of Biochemistry, University of Calcutta, Kolkata, India. Electronic address: maitrayee_d@hotmail.com.
authors.forename: Maitrayee
authors.initials: M
authors.lastname: DasGupta
mesh_terms: D019943:Amino Acid Substitution; D010367:Arachis / Q000201:enzymology; D020134:Catalytic Domain; D008958:Models, Molecular; D009154:Mutation; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D014443:Tyrosine; D011505:Protein-Tyrosine Kinases
keywords: Autoinhibition; Autophosphorylation; Gatekeeper tyrosine; Symbiosis Receptor Kinase