Fast-forward on P-type ATPases: recent advances on structure and function.

P-type ATPase are present in nearly all organisms. They maintain electrochemical gradients for many solutes, in particular ions, they control membrane lipid asymmetry, and are crucial components of intricate signaling networks. All P-type ATPases share a common topology with a transmembrane and three cytoplasmic domains and their transport cycle follows a general scheme - the Post-Albers-cycle. Recently, P-type ATPase research has been advanced most significantly by the technological advancements in cryo-EM analysis, which has elucidated many new P-type ATPase structures and mechanisms and revealed several new ways of regulation. In this review, we highlight the progress of the field and focus on special features that are present in the five subfamilies. Hence, we outline the new intersubunit transport model of KdpFABC, the ways in which heavy metal pumps have evolved to accommodate various substrates, the strategies Ca2+ pumps utilize to adapt to different environmental needs, the intricate molecular builds of the ion binding sites in Na,K- and H,K-ATPases, the remarkable hexameric assembly of fungal proton pumps, the many ways in which P4-ATPase lipid flippases are regulated, and finally the deorphanization of P5 pumps. Interestingly many of the described features are found in more than one of the five subfamilies, and mixed and matched together to provide optimal function and precise regulation.

Structural dynamics of P-type ATPase ion pumps.

P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.