Details

Autor(en) / Beteiligte

• 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

Titel

Identification and functional characterization of the Arabidopsis Snf1‐related protein kinase SnRK2.4 phosphatidic acid‐binding domain

Ist Teil von

• Plant, cell and environment, 2015-03, Vol.38 (3), p.614-624

Ort / Verlag

United States

Erscheinungsjahr

2015

Quelle

Wiley-Blackwell Full Collection

Beschreibungen/Notizen

• 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. This study characterizes the effect of phosphatidic acid (PA) on the cellular localization of a protein kinase that is important for maintaining root growth in saline conditions; SnRK2.4. Membrane affinity and PA‐specificity of SnrK2.4 was shown and a primary PA‐binding site was identified. PA binding is not sufficient for salt‐induced re‐localization, but requires additional domains in the protein. Overexpression of the PA‐binding domain resulted in reduced root growth, possibly by competing for available PA.