Keeping channels open

In the same way a turnstile allows people into a football ground, gating rings allow ions to flow through a cell’s membrane, but its functioning has not been clearly understood.

Gating rings are sensors which open ion channels to allow ions through and are involved in the regulation of crucial bodily activities like blood pressure, insulin secretion and brain signalling. Their biophysical functioning has not been clearly understood, but a team from UCLA have for the first time uncovered the sensor’s molecular mechanism.

Researchers were able to identify how the gating ring is activated and how it rearranges itself to open the gateway through which the ions flow. They studied the BK channel ¬ – a channel present in most cells and regulate fundamental biological processes like blood pressure and muscle contraction in the bladder.

Using electrophysical, biochemical and spectroscopic techniques, the team demonstrated that when calcium ions bind to the gating ring, it changes its structure and coverts the chemical energy of the calcium binding into mechanical work which aids the opening of the BK channel.

“We were able to resolve the biophysical changes occurring in the sensor, under conditions resembling those present inside a living cell, so we believe these transformations reflect the molecular events occurring when BK channels operate in the body,” said lead researcher Riccardo Olcese.

It is only in the last year that BK sensors were identified, but it is believed the channel and its sensor are involved in many aspects of normal physiological function and could be implicated in many aspects of disease. It is hoped the work could lead to the development of specific therapies against hypertension and genetic epilepsy.