Prof. Dr. Tina Romeis
Leibniz Institute for Plant Biochemistry (IPB)
Biochemistry of Plant Interactions
Allelic variation of a vacuolar cation channel modulating ion homeostasis and calcium signalling in plants
Plant cells harbour an organelle of enormous size -the vacuole- which is of crucial importance for processes such as ion storage, osmoregulation, and signalling, that are instrumental for plant development and the adaptation to environmental challenges. These processes all demand the transport of cations across the vacuolar membrane. The most prominent cation channel in this membrane, the TWO PORE CHANNEL 1 (TPC1), regulates ionic balance and systemic calcium signals that initiate cellular downstream responses, such as phosphorylation of target proteins. TPC1 itself is intricately regulated by membrane potential, calcium levels, and phosphorylation.
Allelic polymorphisms in the genomes of 1135 Arabidopsis accessions suggest a functional diversity of the TPC1 protein. Intriguingly, allelic variation clusters in functionally relevant regions of the protein. We hypothesise that these variations have an impact on TPC1 structure and function, resulting in altered ion homeostasis and stress-specific Calcium signal generation and decoding by calcium-dependent protein kinases, ultimately contributing to the adaptation of the plant to its environment. By employing a combination of cell biological, biochemical, electrophysiological, physiological, and computational approaches, this project hence aims to elucidate the relevance of TPC1 proteoform variations for its function and regulation, its physiological roles, and for Calcium signal generation and decoding.
