TY - JOUR A1 - Lohse, Christian A1 - Bock, Andreas A1 - Maiellaro, Isabella A1 - Hannawacker, Annette A1 - Schad, Lothar R. A1 - Lohse, Martin J. A1 - Bauer, Wolfgang R. T1 - Experimental and mathematical analysis of cAMP nanodomains JF - PLoS ONE N2 - In their role as second messengers, cyclic nucleotides such as cAMP have a variety of intracellular effects. These complex tasks demand a highly organized orchestration of spatially and temporally confined cAMP action which should be best achieved by compartmentalization of the latter. A great body of evidence suggests that cAMP compartments may be established and maintained by cAMP degrading enzymes, e.g. phosphodiesterases (PDEs). However, the molecular and biophysical details of how PDEs can orchestrate cAMP gradients are entirely unclear. In this paper, using fusion proteins of cAMP FRET-sensors and PDEs in living cells, we provide direct experimental evidence that the cAMP concentration in the vicinity of an individual PDE molecule is below the detection limit of our FRET sensors (<100nM). This cAMP gradient persists in crude cytosol preparations. We developed mathematical models based on diffusion-reaction equations which describe the creation of nanocompartments around a single PDE molecule and more complex spatial PDE arrangements. The analytically solvable equations derived here explicitly determine how the capability of a single PDE, or PDE complexes, to create a nanocompartment depend on the cAMP degradation rate, the diffusive mobility of cAMP, and geometrical and topological parameters. We apply these generic models to our experimental data and determine the diffusive mobility and degradation rate of cAMP. The results obtained for these parameters differ by far from data in literature for free soluble cAMP interacting with PDE. Hence, restricted cAMP diffusion in the vincinity of PDE is necessary to create cAMP nanocompartments in cells. KW - fluorescence resonance energy transfer KW - yellow fluorescent protein KW - radii KW - adenylyl cyclase signaling cascade KW - cell fusion KW - cytosol KW - isoproterenol KW - absorption KW - cyclic nucleotides such as cyclic adenosine monophosphate Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170972 VL - 12 IS - 4 ER - TY - JOUR A1 - Scholz, Nicole A1 - Guan, Chonglin A1 - Nieberler, Matthias A1 - Grotmeyer, Alexander A1 - Maiellaro, Isabella A1 - Gao, Shiqiang A1 - Beck, Sebastian A1 - Pawlak, Matthias A1 - Sauer, Markus A1 - Asan, Esther A1 - Rothemund, Sven A1 - Winkler, Jana A1 - Prömel, Simone A1 - Nagel, Georg A1 - Langenhan, Tobias A1 - Kittel, Robert J T1 - Mechano-dependent signaling by Latrophilin/CIRL quenches cAMP in proprioceptive neurons JF - eLife N2 - Adhesion-type G protein-coupled receptors (aGPCRs), a large molecule family with over 30 members in humans, operate in organ development, brain function and govern immunological responses. Correspondingly, this receptor family is linked to a multitude of diverse human diseases. aGPCRs have been suggested to possess mechanosensory properties, though their mechanism of action is fully unknown. Here we show that the Drosophila aGPCR Latrophilin/dCIRL acts in mechanosensory neurons by modulating ionotropic receptor currents, the initiating step of cellular mechanosensation. This process depends on the length of the extended ectodomain and the tethered agonist of the receptor, but not on its autoproteolysis, a characteristic biochemical feature of the aGPCR family. Intracellularly, dCIRL quenches cAMP levels upon mechanical activation thereby specifically increasing the mechanosensitivity of neurons. These results provide direct evidence that the aGPCR dCIRL acts as a molecular sensor and signal transducer that detects and converts mechanical stimuli into a metabotropic response. KW - Latrophilin KW - adhesion GPCR KW - dCIRL KW - sensory physiology KW - metabotropic signalling KW - mechanotransduction Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170520 VL - 6 IS - e28360 ER -