%0 Journal Article %1 Gao2001 %A Gao, T. %A Cuadra, A. E. %A Ma, H. %A Bunemann, M. %A Gerhardstein, B. L. %A Cheng, T. %A Eick, R. T. %A Hosey, M. M. %D 2001 %J J Biol Chem %K Animals Barium/pharmacology Calcium Cell Channels, Deletion Fragments/chemistry/pharmacology Humans Kinetics L-Type/*chemistry/drug Line Mammals Membrane Membrane/physiology Patch-Clamp Peptide Potentials/drug Protein Proteins/chemistry/drug Recombinant Sequence Subunits Techniques Transfection effects/*physiology effects/metabolism effects/physiology %N 24 %P 21089-97 %T C-terminal fragments of the alpha 1C (CaV1.2) subunit associate with and regulate L-type calcium channels containing C-terminal-truncated alpha 1C subunits %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11274161 %V 276 %X L-type Ca(2+) channels in native tissues have been found to contain a pore-forming alpha(1) subunit that is often truncated at the C terminus. However, the C terminus contains many important domains that regulate channel function. To test the hypothesis that C-terminal fragments may associate with and regulate C-terminal-truncated alpha(1C) (Ca(V)1.2) subunits, we performed electrophysiological and biochemical experiments. In tsA201 cells expressing either wild type or C-terminal-truncated alpha(1C) subunits in combination with a beta(2a) subunit, truncation of the alpha(1C) subunit by as little as 147 amino acids led to a 10-15-fold increase in currents compared with those obtained from control, full-length alpha(1C) subunits. Dialysis of cells expressing the truncated alpha(1C) subunits with C-terminal fragments applied through the patch pipette reconstituted the inhibition of the channels seen with full-length alpha(1C) subunits. In addition, C-terminal deletion mutants containing a tethered C terminus also exhibited the C-terminal-induced inhibition. Immunoprecipitation assays demonstrated the association of the C-terminal fragments with truncated alpha(1C) subunits. In addition, glutathione S-transferase pull-down assays demonstrated that the C-terminal inhibitory fragment could associate with at least two domains within the C terminus. The results support the hypothesis the C- terminal fragments of the alpha(1C) subunit can associate with C-terminal-truncated alpha(1C) subunits and inhibit the currents through L-type Ca(2+) channels.

@article{Gao2001, abstract = {L-type Ca(2+) channels in native tissues have been found to contain a pore-forming alpha(1) subunit that is often truncated at the C terminus. However, the C terminus contains many important domains that regulate channel function. To test the hypothesis that C-terminal fragments may associate with and regulate C-terminal-truncated alpha(1C) (Ca(V)1.2) subunits, we performed electrophysiological and biochemical experiments. In tsA201 cells expressing either wild type or C-terminal-truncated alpha(1C) subunits in combination with a beta(2a) subunit, truncation of the alpha(1C) subunit by as little as 147 amino acids led to a 10-15-fold increase in currents compared with those obtained from control, full-length alpha(1C) subunits. Dialysis of cells expressing the truncated alpha(1C) subunits with C-terminal fragments applied through the patch pipette reconstituted the inhibition of the channels seen with full-length alpha(1C) subunits. In addition, C-terminal deletion mutants containing a tethered C terminus also exhibited the C-terminal-induced inhibition. Immunoprecipitation assays demonstrated the association of the C-terminal fragments with truncated alpha(1C) subunits. In addition, glutathione S-transferase pull-down assays demonstrated that the C-terminal inhibitory fragment could associate with at least two domains within the C terminus. The results support the hypothesis the C- terminal fragments of the alpha(1C) subunit can associate with C-terminal-truncated alpha(1C) subunits and inhibit the currents through L-type Ca(2+) channels.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Gao, T. and Cuadra, A. E. and Ma, H. and Bunemann, M. and Gerhardstein, B. L. and Cheng, T. and Eick, R. T. and Hosey, M. M.}, biburl = {https://www.bibsonomy.org/bibtex/29aaa48342744e9bc248e39bc9118ae09/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {104086e320b677309e31debf62de1e80}, intrahash = {9aaa48342744e9bc248e39bc9118ae09}, issn = {0021-9258 (Print) 0021-9258 (Linking)}, journal = {J Biol Chem}, keywords = {Animals Barium/pharmacology Calcium Cell Channels, Deletion Fragments/chemistry/pharmacology Humans Kinetics L-Type/*chemistry/drug Line Mammals Membrane Membrane/physiology Patch-Clamp Peptide Potentials/drug Protein Proteins/chemistry/drug Recombinant Sequence Subunits Techniques Transfection effects/*physiology effects/metabolism effects/physiology}, month = {Jun 15}, note = {Gao, T Cuadra, A E Ma, H Bunemann, M Gerhardstein, B L Cheng, T Eick, R T Hosey, M M HL23306/HL/NHLBI NIH HHS/United States T32-DK07169/DK/NIDDK NIH HHS/United States Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. United States The Journal of biological chemistry J Biol Chem. 2001 Jun 15;276(24):21089-97. Epub 2001 Mar 26.}, number = 24, pages = {21089-97}, shorttitle = {C-terminal fragments of the alpha 1C (CaV1.2) subunit associate with and regulate L-type calcium channels containing C-terminal-truncated alpha 1C subunits}, timestamp = {2010-12-14T18:12:11.000+0100}, title = {C-terminal fragments of the alpha 1C (CaV1.2) subunit associate with and regulate L-type calcium channels containing C-terminal-truncated alpha 1C subunits}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11274161}, volume = 276, year = 2001 }