TY  - THES
AB  - During activation of B cells after cross-linking of the B cell receptor phospholipase C g2 (PLCg2) is activated leading to depletion of inositol 1,4,5-trisphosphate sensitive intracellular stores. Following this, Ca2+ channels in the plasmamembrane are opened, which results in a prolonged rise in the cytosolic free Ca2+ concentration. After two decades of research the TRPC family contains the most probable proteins for the molecular identity of these channels, although the regulation of TRPC channels and their composition is still unclear. Subject of the study were the interaction possibilities of three isoforms expressed in murine A20 B-cells: TRPC1, TRPC2 and TRPC3, first with each other and second with further lymphocytic proteins. Furthermore, the role of the N-terminal ankyrin-like repeats and the coiled-coil domain should be deciphered. The results showed that TRPC1, TRPC2 and TRPC3 were able to form homo- as well as heterotetramers, in which the association was facilitated both via the fifth and sixth transmembrane segment including the pore region and via the N-terminus. For the latter the first N-terminal amino acids seemed to be essential. Both the ankyrin-like repeats and the coiled-coil domain possess a regulatory influence on the composition of the channels. In consequence TRPC1 prefers heterotypic interaction with TRPC3 to homotypic interactions. The N-terminal domains are not responsible for the association with the LAT (linker for activation of T-cells) localized in lipid rafts. TRPC1 is tightly bound via its N-Terminus to the actin cytoskeleton. This interaction is probably mediated by tropomodulin 3, the capping protein of the pointed (slowly growing) ends of actin-tropomyosin-filaments. Last but not least a screening of an A20 expression library using the yeast two-hybrid system gave new proof of the association of TRPC1 with several proteins that are connected with transport processes, which supports the model of the secretion-like activation.
DA  - 2004
KW  - B-Zelle , Calciumfreisetzung , Regulation , Calciumkanal , Protein-Protein-Wechselwirkung , TRPC-Proteine , Calciumkanäle , Assemblierung , Regulation , Genbank-Durchmusterung , Immunsystem , TRPC proteins , Calcium channels , Assembly , Regulation , Library screening
LA  - ger
PY  - 2004
TI  - Untersuchung zur Interaktionsfähigkeit in B-Zellen exprimierter TRPC-Proteine und zum Einfluss N-terminaler Domänen
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:361-5150
Y2  - 2024-11-21T22:32:29
ER  -