Trp proteins form store-operated cation channels in human vascular endothelial cells.
Members of the Trp protein family have been suggested as the structural basis of store-operated cation conductances. With this study, we provide evidence for the expression of three isoforms of Trp (hTrp1, 3 and 4) in human umbilical vein endothelial cells (HUVEC). The role of Trp proteins in store regulation of endothelial membrane conductances was tested by expression of an N-terminal fragment of hTrp3 (N-TRP) which exerts a dominant negative effect on Trp channel function presumably due to suppression of channel assembly. Depletion of intracellular Ca2+ stores with IP3 (100 microM) or thapsigargin (100 nM) induced a substantial cation conductance in sham-transfected HUVEC as well as in HUVEC transfected with hTrp3. In contrast, HUVEC transfected with N-TRP failed to exhibit store-operated currents. Our results suggest the involvement of Trp related proteins in the store-operated cation conductance of human vascular endothelial cells.
Groschner
K
K
Institut für Pharmakologie und Toxikologie, Karl-Franzens-Universität Graz, Austria. klaus.groschner@kfunigraz.ac.at
Hingel
S
S
Lintschinger
B
B
Balzer
M
M
Romanin
C
C
Zhu
X
X
Schreibmayer
W
W
D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D006801:Humans; D018408:Patch-Clamp Techniques; D050052:TRPC Cation Channels; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection; D014471:Umbilical Veins
D015220:Calcium Channels; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D019284:Thapsigargin