Original Research ARTICLE
The C-terminal domains SnRK2-box and ABA-box have a role in sugarcane SnRK2s auto-activation and activity
- 1Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas, Brazil
- 2Center for Medicinal Chemistry, Campinas State University, Brazil
- 3Campinas State University, Brazil
- 4Structural Genomics Consortium (Canada), Canada
- 5Structural Genomics Consortium (United Kingdom), United Kingdom
Resistance to drought stress is fundamental to plant survival and development. Abscisic acid (ABA) is one of the major hormones involved in different types of abiotic and biotic stress responses. ABA intracellular signaling has been extensively explored in Arabidopsis thaliana and occurs via a phosphorylation cascade mediated by three related protein kinases, denominated SnRK2s (SNF1-related protein kinases). However, the role of ABA signaling and the biochemistry of SnRK2 in crop plants remains underexplored. Considering the importance of the ABA hormone in abiotic stress tolerance, here we investigated the regulatory mechanism of sugarcane SnRK2s - known as SAPKs (Stress/ABA-activated Protein Kinases). The crystal structure of ScSAPK10 revealed the characteristic SnRK2 family architecture, in which the regulatory SnRK2-box interacts with the kinase domain αC helix. To study sugarcane SnRK2 regulation, we produced a series of mutants for the protein regulatory domains SnRK2-box and ABA-box. Mutations in ScSAPK8 SnRK2-box aimed at perturbing its interaction with the protein kinase domain reduced protein kinase activity in vitro. On the other hand, mutations to ScSAPK ABA-box did not impact protein kinase activity but did alter the protein autophosphorylation pattern. Taken together, our results demonstrate that both SnRK2- and ABA-boxes might play a role in sugarcane SnRK2 function.
Keywords: Abscisic Acid, abiotic stress, SnRK2, Crop plant, kinase regulation, sugarcane
Received: 27 Mar 2019;
Accepted: 12 Aug 2019.
Edited by:Jos Schippers, Abteilung Molekulare Genetik, Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Germany
Reviewed by:Jorge Lozano-Juste, Institute of Molecular and Cellular Biology of Plants, Polytechnic University of Valencia, Spain
Grazyna Dobrowolska, Institute of Biochemistry and Biophysics (PAN), Poland
Copyright: © 2019 Righetto, Sriranganadane, Halabelian, Chiodi, Elkins, Massirer, Gileadi, Menossi and Couñago. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: PhD. Rafael M. Couñago, Center for Medicinal Chemistry, Campinas State University, Campinas, Brazil, firstname.lastname@example.org