The 30th International Conference on Arabidopsis Research (ICAR 2019)

719 / 2019-05-09 12:10:49

Regulation of plant growth by polarly distributed AGC kinases

polarity,protein kinase,protein phosphorylation,auxin,auxin trasport

Plenary track > Hormones

The directional transport of the phytohormone auxin through polarly localized PIN-FORMED (PIN) auxin efflux carriers is essential for the spatio-temporal control of plant development. The Arabidopsis thaliana AGC kinase D6 PROTEIN KINASE (D6PK) as well as related kinases are polarly localized at the plasma membrane of many cells where D6PK co-localizes with PINs and activates PIN-mediated auxin efflux. The fast cycling of D6PK to and from the basal plasma membrane indicates that this kinase could act as a switch for polar auxin transport and makes it an intriguing subject for further studies. We have shown that an insertion between the protein kinase subdomains VII and VIII, the middle domain, is necessary and sufficient for its polar plasma membrane association. Conserved motifs within the middle domain play a role in kinase localization and activity. One motif in the middle domain interacts with phosphoinositides but there are also other, as yet mechanistically not understood sequence features in this domain. Current progress in the understanding of D6PK polarity regulation will be presented. A further focus will be on the activity and regulation of AGC kinases related to D6PK that function in root hair and pollen tube growth.