STIM1 and ORAI1 (also termed CRACM1) are essential components of the classical calcium release-activated calcium current; however, the mechanism of the transmission of information of STIM1 to the calcium release-activated calcium/ORAI1 channel is as yet unknown. Here we demonstrate by Förster resonance energy transfer microscopy a dynamic coupling of STIM1 and ORAI1 that culminates in the activation of Ca 2؉ entry. Förster resonance energy transfer imaging of living cells provided insight into the time dependence of crucial events of this signaling pathway comprising Ca 2؉ store depletion, STIM1 multimerization, and STIM1-ORAI1 interaction. Accelerated store depletion allowed resolving a significant time lag between STIM1-STIM1 and STIM1-ORAI1 interactions. Store refilling reversed both STIM1 multimerization and STIM1-ORAI1 interaction. The cytosolic STIM1 C terminus itself was able, in vitro as well as in vivo, to associate with ORAI1 and to stimulate channel function, yet without ORAI1-STIM1 cluster formation. The dynamic interaction occurred via the C terminus of ORAI1 that includes a putative coiled-coil domain structure. An ORAI1 C terminus deletion mutant as well as a mutant (L273S) with impeded coiled-coil domain formation lacked both interaction as well as functional communication with STIM1 and failed to generate Ca 2؉ inward currents. An N-terminal deletion mutant of ORAI1 as well as the ORAI1 R91W mutant linked to severe combined immune deficiency syndrome was similarly impaired in terms of current activation despite being able to interact with STIM1. Hence, the C-terminal coiled-coil motif of ORAI1 represents a key domain for dynamic coupling to STIM1.

In this paper we report an alternative sintering method for conductive silver tracks by UV radiation. The silver patterns have been obtained by inkjet printing from a commercially available silver nanoparticle ink. Different polymer materials such as polyimide, polycarbonate and liquid crystal polymer have been used as substrate materials. UVcuring resulted in highly conductive patterns with resistivities as low as four times that of bulk silver. The choice of substrate material has shown to greatly influence the achievable conductivity values. Furthermore it was demonstrated that UVsintering resulted in lower substrate temperature as compared to thermal sintering to get similar resistance values.

ZusammenfassungDigitale kontaktlose Drucktechnologien wie Inkjet oder Aerosol Jet

No abstract

This paper summarizes the results on inkjet printing and characterization of functional structures on molded 2D and 3D devices. Different injection molded thermoplastics, a transfer molded thermoset and polyimide foil as substrate materials were used. Conductive structures were obtained by inkjet printing of a commercial available silver nanoparticle ink. The use of printable acrylic based ink enabled the fabrication of conductor crossovers or multilayers. Results on inkjet printed temperature sensitive structures and an inkjet printed intrusion sensor device as well as an inkjet printed electrical interconnect on a transfer molded package will be presented.