Project Emmy Noether Project: R-SNARE K-channel interactions in coordinating vesicle trafficking and ion transport

Basic data

Title:
Emmy Noether Project: R-SNARE K-channel interactions in coordinating vesicle trafficking and ion transport
Duration:
01/05/2013 to 30/04/2018
Abstract / short description:
Vesicle trafficking is enabled by a complex interplay of protein-protein interactions. Key players are the so-called SNARE proteins facilitating the actual membrane fusion through a tight interaction of their intrinsic SNARE motifs that helps to overcome the strong dehydration forces associated with lipid bilayers. Both membrane and vesicle feature a specific subset of SNAREs: Q- and R-SNAREs. Until recently, understanding of SNARE function centred on their canonical role in vesicle fusion. A novel interaction of the Q-SNARE SYP121 with the K-channel subunit KC1 in Arabidopsis thaliana challenged our view of SNAREs being solely involved in facilitating membrane fusions. Under K-limiting conditions, loss-of-function lines of SYP121 phenocopy the reduced growth of corresponding K-channel knockouts. Complementary, root impalements of syp121 lines show loss of inward K-currents suggesting a regulatory role on channel activity, probably through direct modulation of its gating behaviour. Interestingly, the mechanism of the interaction is executed through a novel motif at the N-terminus of the SNARE. This motif lies beyond previously identified SNARE domains which are implicated in core complex formation. These findings allow new hypotheses on additional, non-canonical roles of SNARE proteins.
This proposal is based on our recent discovery that specific members of the R-SNARE family interact with K-channels as well. Research on R-SNAREs at present mainly focusses on their role in vesicle trafficking and is largely based on findings in the animal field. In plants, pathogen resistance and cytokinesis are dependent on R-SNAREs canonical function in directing and driving vesicle-trafficking. A functional role of the interaction of an R-SNARE with K-channels will allow an alternative approach for understanding SNARE function in general and its involvement in K-channel regulation in particular. Questions that will be addressed within the scope of this project should 1.) lead to a detailed understanding of the molecular mechanism of the interaction, 2.) resolve trafficking-related effects in connection with the SNARE-channel interaction and 3.) explain functional consequences in plant growth and development. Dissecting the involvement of different types of SNAREs in K-channel interaction is likely to yield a mechanistic view involving either competition of the SNAREs or sequential binding. Elucidating the mechanism of SNARE-channel interaction as a dynamic process linking vesicle trafficking with ion transport is expected to lead to a paradigm shift for SNARE function in general.

Involved staff

Managers

Department of Biology
Faculty of Science

Local organizational units

Center for Plant Molecular Biology (ZMBP)
Department of Biology
Faculty of Science

Funders

Bonn, Nordrhein-Westfalen, Germany
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