A primer on resolving the nanoscale structure of the plasma membrane with light and electron microscopy
Taraska reviews the imaging methods that are being used to understand the structure of the plasma membrane at the molecular level.
Among the three two-pore channels (TPCs), TPC1 and TPC2 are selectively activated by PI(3,5)P2, while TPC3 has been considered not to respond to any PIP2s. Shimomura and Kubo find that TPC3 responds to both PI(3,5)P2 and PI(3,4)P2, but not to PI(4,5)P2.
Myosin lever arm orientation in muscle determined with high angular resolution using bifunctional spin labels
High-resolution structural information is invaluable for understanding muscle function. Savich et al. use bifunctional spin labeling to determine the orientation of the myosin lever arm in muscle fibers at high resolution under ambient conditions, augmenting previous insights obtained from fluorescence and EM.
Dendritic spine geometry and spine apparatus organization govern the spatiotemporal dynamics of calcium
Dendritic spines can have numerous different shapes, but how this affects the function of these neuronal subcompartments is unclear. Bell et al. develop a mathematical model that reveals how the size and shape of both the spine head and spine apparatus impact local calcium dynamics.
Erdem et al. compare the kinetics of the SLC6 family glycine transporters GlyT1 and GlyT2. Though the two transporters are rate-limited by distinct reaction steps, they both display high transport capacity, with the kinetics of GlyT1 sufficient to supply extracellular glycine to the NMDA receptor.
Heart rate is set by the specialized tissue of the sinoatrial node. Lin et al. demonstrate a novel role for phosphoinositide 3-kinase in regulating cardiac pacemaking currents independently of the autonomic nervous system, a finding with relevance for diabetes, heart disease, and cancer.