Biophysical Society Bulletin | October 2019

Communities

The deadline for Cole Award nominations is Friday, October 25, 2019. Nominations should be sent to Matt Trudeau , Sub- group Secretary-Treasurer, at mtrudeau@som.umaryland.edu by 11:59 pm EST. The Cole award will be presented following the Subgroup symposium at the Cole Award dinner. The dinner features a talk by the Cole awardee and takes place from 6 pm to 9 pm on Saturday, February 15, 2020, at the Water Grill in San Diego, CA. Please access the webpage below to join or renew your membership in the Subgroup and to register for the 2020 Cole Award Dinner. https:/www.biophysics.org/store/products/product- details?ProductName=2020-channels-receptors- transporters-subgroup The award recipient will be selected by the Awards Com- mittee. The Awards Committee is established annually and consists of the Chair, the Chair-elect, the past-Chair and two Subgroup members who are not Subgroup officers, and who will be appointed by the Chair for a one-year term. — Matt Trudeau, Secretary-Treasurer Membrane Transport Subgroup The Membrane Transport Subgroup will hold our symposium on the afternoon of February 15, 2020, in San Diego, Califor- nia. We are excited to introduce our speakers: Osamu Nureki , University of Tokyo, Japan Grace Brannigan , Rutgers University, USA Randy Stockbridge , University of Michigan, USA Jose Faraldo-Gomez , National Institutes of Health, USA Katherine Henzler-Wildman , University of Wisconsin, Madison, USA Students and postdocs take note: two of you will be selected to speak based on abstracts submitted to the BPS Annual Meeting. Continuing our tradition of using the BPS Bulletin as a platform to highlight works by our Subgroup members, we include here notes about recent publications by Steve Long’s group at the Memorial Sloan Kettering Institute (Fig. 1) and Simon Scheur- ing’s group at Weill Cornell Medical School (Fig. 2). “Bestrophin (BEST1-4) Ligand-gated Chloride (Cl-) Chan- nels are Activated by Calcium (Ca2+).” Miller *, Vaisey * and Long (eLife 2019; *equal contribution) presented a series of high-resolution cryo-EM structures of BEST1 that repre- sent the principal gating states of the channel. Unlike other channels, opening of the pore is due to the repositioning of

tethered pore-lining helices within a surrounding protein shell that dramatically widens a neck of the pore. The opening transition is akin to local protein refolding and involves a concertina of amino acid rearrangements. They discovered the neck functions as both the activation and the inactivation gate and defines a new molecular paradigm for gating among ligand-gated ion channels.

Figure 1. Structures of BEST1 from the Long lab in the closed and open conformations, showing the neck regions. Amino acids forming the gate (red) undergo substantial reposition- ings that widen the neck and are accommodated by associat- ed changes in other amino acids throughout the channel (e.g., green). Piezo channels are mechanosensitive, nonselective cation channels that detect force in eukaryotic cells. The transduc- tion of mechanical stimuli is important in many different physiological processes, including touch sensation. Scheuring and co-workers used high-speed atomic force microscopy during a force-sweep cycle to measure the in-plane expan- sion of Piezo1 as a function of applied force. They found that mechanical force induces conformational changes in Piezo1 that could explain gating in response to mechanical perturba- tions (Nature, 2019).

Figure 2. High-speed atomic force microscopy (HS-AFM) kymograph during a force-sweep cycle of the in-plane ex- pansion of Piezo1 as a function of applied force (top). Pro- posed model of Piezo1 flattening into the membrane plane In response to a mechanical stimulus as the gating mechanism (bottom). — Susan Rempe , Chair; Ming Zhou , Vice Chair; Lucie Delemotte , Secretary–Treasurer

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