Computational Biology
Metal homeostasis
Manganese (Mn) is an essential micronutrient with special importance for photosynthetic organisms due to its function in water oxidation. To avoid critical imbalances, Mn needs to be specifically and timely allocated to the place where it is needed, and sequestered in a safe storage place if accumulating in excess. That is, key to Mn homeostasis is the controlled uptake from the environment and appropriate intracellular distribution of the metal. Our research aims at a mechanistical understanding of manganese (Mn) homeostasis in oxygenic photosynthetic organisms. To identify evolutionary conserved proteins involved in Mn homeostasis and its management, we are performing our studies in the cyanobacterium Synechocystis sp. PCC 6803 and the land plant Arabidopsis thaliana in parallel.
Current projects Eisenhut
Manganese in Synechocystis
We have identified the Unknown Protein Family (UPF) 0016 as a new group of Mn transporter. The founding member Manganese exporter (Mnx) in the model cyanobacterium Synechocystis sp. PCC6803 facilitates Mn transport from the cytoplasm into the thylakoid lumen and is involved in Mn delivery to Photosystem II as well as sequestration of excess Mn. Mnx-type transporters were endosymbiontically conveyed to plants and are here constituting efficient Mn uptake systems at the chloroplast envelope and the thylakoid membrane. Two additional UPF0016 members, Hemi manganese exchangers (Hmx) Hmx1 and Hmx2, are exclusively encoded in cyanobacterial genomes and function here as the long sought constitutive Mn importer at the plasma membrane.
Furthermore, players involved in cellular Mn homeostasis are under transcriptional regulation. Using RNA-seq DAP-seq experiments we aim at the identification of transcription factors involved the management of Mn homeostasis.