GET pathway receptors in plants

• Applicant: Professor Dr. Christopher Grefen
• Subject Area: Plant Cell and Developmental Biology ; Plant Physiology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543964888

In contrast to the cotranslational insertion of membrane proteins into the endoplasmic reticulum (ER), the absence of an N-terminal signal sequence or membrane domain in a variety of integral membrane proteins necessitates their post-translational insertion. Several years ago, a pathway was discovered in yeast and mammalian cells, the partial conservation of which has also been confirmed in plants. This pathway, known as the "Guided-Entry of Tail-anchored proteins" (GET), comprises proteins that intercept the newly emerging membrane protein at the ribosome, transfer it to a chaperone (GET3a), and guide it through the cytosol to two specific receptors on the ER membrane (GET1 and GET2). In Arabidopsis, the absence of one or more GET components leads to a defect in root hair growth. At the heart of this proposal, we employ cell physiological and biochemical methods to explore the intricate interplay between the two GET receptors, in conjunction with the chaperone GET3a and a recently identified interacting partner, the PI(4)P phosphatase Root Hair Defective 4 (RHD4). More specifically, our approach involves targeted mutagenesis, diverse protein-protein interaction techniques, and complementation analyses of loss-of-function lines. The primary goal is to delineate the binding domains within the receptors, illuminate their impact on the functionality of the GET pathway, and clarify the physiological significance of the interaction with a PI4P phosphatase. Ultimately, the results are poised to enhance our understanding of the function of the GET pathway in plants and unravel the underlying mechanisms behind the root hair phenotype observed in loss-of-function lines.

• DFG Programme: Research Grants