|Title||Identification and functional characterization of the Arabidopsis Snf1-related protein kinase SnRK2.4 phosphatidic acid-binding domain|
|Author(s)||Julkowska, Magdalena M.; McLoughlin, Fionn; Galvan-Ampudia, Carlos S.; Rankenberg, Johanna M.; Kawa, Dorota; Klimecka, Maria; Haring, Michel A.; Munnik, Teun; Kooijman, Edgar E.; Testerink, Christa|
|Source||Plant, Cell & Environment 38 (2015)3. - ISSN 0140-7791 - p. 614 - 624.|
|Department(s)||Laboratory of Plant Physiology|
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||phosphatidic acid - phospholipid binding - root system architecture - SnRK2.10|
Phosphatidic acid (PA) is an important signalling lipid involved in various stress-induced signalling cascades. Two SnRK2 protein kinases (SnRK2.4 and SnRK2.10), previously identified as PA-binding proteins, are shown here to prefer binding to PA over other anionic phospholipids and to associate with cellular membranes in response to salt stress in Arabidopsis roots. A 42 amino acid sequence was identified as the primary PA-binding domain (PABD) of SnRK2.4. Unlike the full-length SnRK2.4, neither the PABD-YFP fusion protein nor the SnRK2.10 re-localized into punctate structures upon salt stress treatment, showing that additional domains of the SnRK2.4 protein are required for its re-localization during salt stress. Within the PABD, five basic amino acids, conserved in class 1 SnRK2s, were found to be necessary for PA binding. Remarkably, plants overexpressing the PABD, but not a non-PA-binding mutant version, showed a severe reduction in root growth. Together, this study biochemically characterizes the PA-SnRK2.4 interaction and shows that functionality of the SnRK2.4 PABD affects root development.