Evolutionary change of GBF1-type ARF-GEF to plant-specific GNOM – novel domain interaction and biological function

• Applicant: Professor Dr. Gerd Jürgens
• Subject Area: Plant Cell and Developmental Biology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 492659015

About one third of the eukaryotic proteins are delivered via membrane traffic to their sites of action or destruction. Activating small ARF GTPases, ARF guanine-nucleotide exchange factors (ARF-GEFs) play essential regulatory roles in membrane trafficking. A class of large ARF-GEFs comprising mammalian GBF1 and plant GNOM have a conserved domain organization (N-terminal dimerization domain DCB, HUS domain, catalytic domain SEC7, 3 additional domains HDS1-3). However, these ARF-GEFs differ in their mode of domain interaction (DCB-HUS in GBF1, DCB-delta DCB in GNOM) and their sites of action (retrograde COPI traffic from Golgi to ER in GBF1, polar recycling of auxin transporter PIN1 from endosomes to the basal plasma membrane in GNOM). This proposal addresses the evolutionary change of ARF-GEF function from GBF1-type to GNOM-type. In continuation of the current project, we will define the phylogenetic place of change from DCB-HUS to DCB-delta DCB interaction. We will also analyze, as a new problem, additional steps of the functional change from GBF1-type to GNOM-type ARF-GEFs in plant evolution. In addition, we will continue to analyze the mechanism(s) underlying DCB-delta DCB interaction in GNOM.

• DFG Programme: Research Grants