Ongoing projects

Mechanisms of Stomatin regulation of Acid-sensing ion channels

We are currently trying to understand how a family of Stomatin-domain containing proteins regulate ASICs. Current evidence suggests that the Stomatin family of proteins interact with ASICs and dramatically reduce their currents in an isoform-dependent manner. We are seeking to understand how Stomatins accomplish this feat.

Lipid regulation of ASICs

We are examining the structural determinants of lipid regulation of ASICs. Previous work has shown that polyunsaturated fatty acids can potentiate ASICs but the mechanism of this action is completely unknown. We are using patch clamp electrophysiology in a heterologous cell system as well as in neurons to understand the role that these ubiquitous lipids play in ASIC gating.

Structural mechanisms of proton dependent gating in ASICs

We are using tmFRET and DEER (see research page) to look at how proton binding to a site in the extracellular domain of ASICs leads to the opening of a gate over 50 angstroms away. In the short-term we are asking specific questions about the conformational changes in specific regions of ASIC. In the long term, we would like to use these data to build an overall model for ASIC gating.

What is the role that ASIC1a plays in stroke?

There is a great deal of evidence that suggests that blockade of ASIC1a or genetic removal of ASIC1a can dramatically reduce cell death in stroke. There are a number of hypotheses for how this might be happening and we are using patch clamp electrophysiology, FRET, imaging, and structural techniques to try and understand the role that ASICs play.

How do a novel family of ER proteins regulate HCN4 channels

We are also working in collaboration with the Proenza lab at CU Anschutz on a family of novel regulators of HCN4 channels. These two proteins, LRMP and IRAG, each bind to a regulate HCN4. However, the result of their binding is different in each protein. In addition, both proteins appear to be specific regulators of HCN4 and do not affect the other HCN4 isoforms. We are interested in understanding how these proteins bind to and regulate HCN4 and also what the physiological and cellular consequences are for formation of these complexes.

 

Future projects for interested students and postdocs

ASIC stoichiometry

ASICs are known to be trimers and they can form both homo- and heterotrimers, but little is known about how they do this. We are interesting in using a number of cutting edge fluorescence approaches including FIR, SpiDa, and single molecule apporaches to see if we can understand heteromer formation in ASICs.

Structural studies of the macromolecular complexes that sense pH which includes ASICs, Stomatins, PSD95, PICK1, and many more proteins.

Discovery of novel small molecular inhibitors and activators of ASICs.