Aktivierung der membranständigen Guanylatzyklase ROS-GC1 durch Ca(2+)-bindende Proteine

Cyclic GMP is the second messenger in vertebrate phototransduction. Two isoforms of membrane-bound guanylate cyclase, ROS-GC1 and 2, have been found in photoreceptor outer segments and are activated by low ]free. Ca2+ -sensitivity is mediated by the lipid-modified activator proteins GCAP-1 through -3. In other tissues, ROS-GC1 is stimulated by high ]free via S100b and the lipidated Ca2+ sensor protein neurocalcin , respectively. Detailed structural information on the membrane-bound complexes of ROS-GC1 with its activators is currently not available. The aim of this new project is to reveal how the various regulatory Ca2+-binding proteins interact with the guanylate cyclase in its membrane environment, and how differential regulation is achieved.