May 2016 | Volume 147, No. 5
- Structure–function relationships of peptides forming the calcin family of ryanodine receptor ligands
Calcins are a new and expanding family of ryanodine receptor agonists found in scorpion venom. Xiao and colleagues characterize the structure–function relationships of all known calcins and show both similarities and differences in their form and function.
- Functional characterization of orbicularis oculi and extraocular muscles
Facial muscles are skeletal muscles that control facial expression. Sekulic-Jablanovic et al. characterize orbicularis oculi and extraocular muscles and find divergence in the expression of key molecules for muscle function between facial, extraocular, and quadriceps muscles.
- Spatial positioning of CFTR’s pore-lining residues affirms an asymmetrical contribution of transmembrane segments to the anion permeation pathway
CFTR is a chloride channel and a member of the ABC transporter superfamily; however, its structure is unknown. By making a series of cysteine mutants, Gao and Hwang show that CFTR lacks the twofold pseudo-symmetry seen in the permeation pathway of bone fide ABC transporters.
- Ae4 (Slc4a9) is an electroneutral monovalent cation-dependent Cl−/HCO3− exchanger
AE4 is an anion exchanger known to counter transport Cl− and HCO3− across secretory cell membranes. Peña-Münzenmayer et al. show that AE4 is an electroneutral exchanger and that it also transports monovalent cations in the same direction as HCO3−.