New clues to the structural dynamics of BK channels

July 14, 2011

BK channels (large-conductance, Ca2+-dependent K+ channels) are essential for the regulation of important biological processes such as smooth muscle tone and neuronal excitability. New research shows that BK channel activation involves structural rearrangements formerly not understood. The study appears in the August 2011 issue of the Journal of General Physiology.

Previous research pointed to a possible unified theory of activation gating in K+ channels, with the "activation gate" formed by the bundle crossing of four S6 transmembrane helices from the four subunits. Recent studies, however, have suggested a different structure for BK channels, but the exact location of the activation gate remained a mystery.

A new study by Xixi Chen and Richard Aldrich (The University of Texas at Austin) provides important clues to this question. The research identifies a single residue M314, halfway down S6, that appears to change conformation during the opening of the BK channel, rotating its side chain from a position in the closed state not exposed to the hydrophilic pore to one that is so exposed in the open state. The results further show that M314 might not actually form the part of the activation gate that blocks ion passage, but that motions in the deep pore may be required for blocking ion passage elsewhere in the channel.

The findings point to new directions for research regarding the of BK channel activation, according to Commentary by Daniel Cox (Tufts University School of Medicine) and Toshinori Hoshi (University of Pennsylvania). Importantly, they say, the study demonstrates that activation is not an open-and-shut case as previously suspected.

More information: Cox, D.H., and T. Hoshi. 2011. J. Gen. Physiol. doi:10.1085/jgp.201110681.
Chen, X., and R.W. Aldrich. 2011. J. Gen. Physiol. doi:10.1085/jgp.201110632.

Related Stories

Recommended for you

Rac1 protein critical for lung development

October 20, 2016

A study by researchers from The Saban Research Institute of Children's Hospital Los Angeles reveals a promising therapeutic target for improving lung function in infants. Their study, now published online by the American ...

A vitamin could help treat Duchenne muscular dystrophy

October 19, 2016

Duchenne is the most common and severe form of muscular dystrophy. Because of this genetic disease, one out of every 3,500 children spends their 12th birthday in a wheelchair. This disorder progressively leads to general ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.