Determining how regulatory parameters dictate active membrane transport

Active transport of ions across biological membranes by ATP-dependent (P-type) transmembrane proteins plays a pivotal role in signaling processes across both eukaryotes and prokaryotes.

Dynamic regulation of active ion transport is essential to meet varying cellular demands at local, membrane-specific, and organism levels – and to maintain energy balance.

Disturbances in this regulation can cause human disease, such as heart failure and Wilson’s disease – but is also a potential venue for new antibiotics against pathogenic bacteria.

Simultaneous tracking of protein kinetics and structural rearrangements can provide mechanistic understanding of such regulation.

We will use time-resolved X-ray solution scattering, cryo-EM, and neutron scattering techniques to determine shifts in protein intermediate-state distributions, kinetics, and structural conformations in both external and internal control of P-type ATPase transport.

Specifically, we will characterize how domain arrangements and kinetic distributions of transient intermediate states in solution are influenced by lipid chemistry (bacterial Ca2+ ATPases), internal domains (bacterial Zn2+ ATPases, human Cu+ATPases, and SERCA2b), and therapeutic compounds (eukaryotic SERCA2a).

The results will provide insights into structural ensemble dynamics and kinetics, link the obtained structural regulatory mechanisms in the time regime, and may also be applicable to other membrane proteins like ion channels and receptors.