Playing with transmembrane signals.

Membrane proteins are abundant in nature and play a key role in many essential life processes. They typically span the membrane with one or more hydrophobic segments. Temporal changes in properties of such transmembrane (TM) segments often are a prerequisite for functional activity of membrane proteins. However, very little is known about the molecular nature of this important step in signaling. In a recent published work, we report the finding that both the sensing and transmission of DesK, a bacterial cold sensor, which has five TM segments, can be captured into a chimerical single membrane-spanning minimal sensor. Thus, the DesK system allows minimization of a complex phenomenon to a perfect functional system. This "minimalist" approach helped to uncover the modus operandis of a receptor for environmental cold, but also explores the use of a novel approach to study how the TM domains of a sensor protein transmit signals across membranes.