Complex Formation between Junctin, Triadin, Calsequestrin, and the Ryanodine Receptor. PROTEINS OF THE CARDIAC JUNCTIONAL SARCOPLASMIC RETICULUM MEMBRANE Export

@article{citeulike:3504851, abstract = {Several key proteins have been localized to junctional sarcoplasmic reticulum which are important for Ca2+ release. These include the ryanodine receptor, triadin, and calsequestrin, which may associate into a stable complex at the junctional membrane. We recently purified and cloned a fourth component of this complex, junctin, which exhibits homology with triadin and is the major 125I-calsequestrin-binding protein detected in cardiac sarcoplasmic reticulum vesicles (Jones, L. R., Zhang, L., Sanborn, K., Jorgensen, A. O., and Kelley, J. (1995) J. Biol. Chem. 270, 30787-30796). In the present study, we have examined the binding interactions between the cardiac forms of these four proteins with emphasis placed on the role of junctin. By a combination of approaches including calsequestrin-affinity chromatography, filter overlay, immunoprecipitation assays, and fusion protein binding analyses, we find that junctin binds directly to calsequestrin, triadin, and the ryanodine receptor. This binding interaction is localized to the lumenal domain of junctin, which is highly enriched in charged amino acids organized into "KEKE" motifs. KEKE repeats are also found in the common lumenal domain of triadin, which likewise is capable of binding to calsequestrin and the ryanodine receptor (Guo, W., and Campbell, K. P. (1995) J. Biol. Chem. 270, 9027-9030). It appears that junctin and triadin interact directly in the junctional sarcoplasmic reticulum membrane and stabilize a complex that anchors calsequestrin to the ryanodine receptor. Taken together, these results suggest that junctin, calsequestrin, triadin, and the ryanodine receptor form a quaternary complex that may be required for normal operation of Ca2+ release. 10.1074/jbc.272.37.23389}, author = {Zhang, Lin and Kelley, Jeff and Schmeisser, Glen and Kobayashi, Yvonne M. and Jones, Larry R.}, citeulike-article-id = {3504851}, citeulike-linkout-0 = {http://dx.doi.org/10.1074/jbc.272.37.23389}, citeulike-linkout-1 = {http://www.jbc.org/cgi/content/abstract/272/37/23389}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/9287354}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=9287354}, day = {12}, doi = {10.1074/jbc.272.37.23389}, journal = {J. Biol. Chem.}, keywords = {ca-handling-proteins, calcium-buffers, junctin, junctional-sr, ryr, ryr-regulation, triadin}, month = {September}, number = {37}, pages = {23389--23397}, posted-at = {2008-11-12 03:03:11}, priority = {2}, title = {Complex Formation between Junctin, Triadin, Calsequestrin, and the Ryanodine Receptor. PROTEINS OF THE CARDIAC JUNCTIONAL SARCOPLASMIC RETICULUM MEMBRANE}, url = {http://dx.doi.org/10.1074/jbc.272.37.23389}, volume = {272}, year = {1997} }

TY - JOUR ID - citeulike:3504851 L3 - citeulike-article-id:3504851 N2 - Several key proteins have been localized to junctional sarcoplasmic reticulum which are important for Ca2+ release. These include the ryanodine receptor, triadin, and calsequestrin, which may associate into a stable complex at the junctional membrane. We recently purified and cloned a fourth component of this complex, junctin, which exhibits homology with triadin and is the major 125I-calsequestrin-binding protein detected in cardiac sarcoplasmic reticulum vesicles (Jones, L. R., Zhang, L., Sanborn, K., Jorgensen, A. O., and Kelley, J. (1995) J. Biol. Chem. 270, 30787-30796). In the present study, we have examined the binding interactions between the cardiac forms of these four proteins with emphasis placed on the role of junctin. By a combination of approaches including calsequestrin-affinity chromatography, filter overlay, immunoprecipitation assays, and fusion protein binding analyses, we find that junctin binds directly to calsequestrin, triadin, and the ryanodine receptor. This binding interaction is localized to the lumenal domain of junctin, which is highly enriched in charged amino acids organized into "KEKE" motifs. KEKE repeats are also found in the common lumenal domain of triadin, which likewise is capable of binding to calsequestrin and the ryanodine receptor (Guo, W., and Campbell, K. P. (1995) J. Biol. Chem. 270, 9027-9030). It appears that junctin and triadin interact directly in the junctional sarcoplasmic reticulum membrane and stabilize a complex that anchors calsequestrin to the ryanodine receptor. Taken together, these results suggest that junctin, calsequestrin, triadin, and the ryanodine receptor form a quaternary complex that may be required for normal operation of Ca2+ release. 10.1074/jbc.272.37.23389 IS - 37 JF - J. Biol. Chem. EP - 23397 TI - Complex Formation between Junctin, Triadin, Calsequestrin, and the Ryanodine Receptor. PROTEINS OF THE CARDIAC JUNCTIONAL SARCOPLASMIC RETICULUM MEMBRANE VL - 272 SP - 23389 KW - ca-handling-proteins KW - calcium-buffers KW - junctin KW - junctional-sr KW - ryr KW - ryr-regulation KW - triadin AU - Zhang, Lin AU - Kelley, Jeff AU - Schmeisser, Glen AU - Kobayashi, Yvonne AU - Jones, Larry PY - 1997/09/12/ UR - http://dx.doi.org/10.1074/jbc.272.37.23389 ER -