This is a plant biology project using the model system Arabidopsis thaliana to investigate protein functions related to membrane dynamics and iron transporter regulation. A combination of biochemistry, molecular biology, cell biology/fluorescence microscopy and plant biology techniques will be applied.

The zinc (Zn) and iron (Fe) permease IRON-REGULATED TRANSPORTER1 (IRT1), essential for divalent iron uptake from the soil into the root, is regulated by metal ions at multiple levels, including protein stability, trafficking and localization at the plasma membrane. IRT1 contains a large cytosolic loop domain, that is important for protein function and regulation. We have identified IRT1 cytosolic loop interaction partners (= ICLIPs), mainly peripheral membrane proteins, that may act as molecular anchors to affect dynamic processes at the face of membranes. One ICLIP, the C2 domain protein EHB1/CAR6, is a negative regulator of IRT1. Our aim is to uncover the roles of ICLIPs in the context of Fe acquisition and Fe signaling. 

We will test two main hypotheses: First, ICLIP interactions may serve to balance the beneficial and toxic sides of ferrous Fe uptake across the membrane. Second, ICLIPs may regulate IRT1 protein activity and stability by linking Fe signaling at the membrane with endomembrane trafficking.

Through mutagenesis and functional mapping, we will determine protein functions and functional domains, membrane association and protein interactions, using in vitro, cellular and in planta assays, by combining biochemical approaches and advanced microscopic imaging studies. In the long run of this CRC, we will unravel the mechanistic and structural principles that regulate IRT1 and affect metal uptake and trafficking.

Project leader: Prof. Dr. Petra Bauer,

Researchers:  Jannik Hornbergs,
                            Hadeel Khalouf,
                            Inga Mohr,