Three-dimensional electron microscopy reveals new details of membrane systems for Ca2+ signaling in the heart Export

@article{citeulike:4537471, abstract = {In the current study, the three-dimensional (3D) topologies of dyadic clefts and associated membrane organelles were mapped in mouse ventricular myocardium using electron tomography. The morphological details and the distribution of membrane systems, including transverse tubules (T-tubules), junctional sarcoplasmic reticulum (SR) and vicinal mitochondria, were determined and presumed to be crucial for controlling cardiac Ca2+ dynamics. The geometric complexity of T-tubules that varied in diameter with frequent branching was clarified. Dyadic clefts were intricately shaped and remarkably small (average 4.39x105 nm3, median 2.81x105 nm3). Although a dyadic cleft of average size could hold maximum 43 ryanodine receptor (RyR) tetramers, more than one-third of clefts were smaller than the size that is able to package as many as 15 RyR tetramers. The dyadic clefts were also adjacent to one another (average end-to-end distance to the nearest dyadic cleft, 19.9 nm) and were distributed irregularly along T-tubule branches. Electron-dense structures that linked membrane organelles were frequently observed between mitochondrial outer membranes and SR or T-tubules. We, thus, propose that the topology of dyadic clefts and the neighboring cellular micro-architecture are the major determinants of the local control of Ca2+ in the heart, including the establishment of the quantal nature of SR Ca2+ releases (e.g. Ca2+ sparks). 10.1242/jcs.028175}, author = {Hayashi, Takeharu and Martone, Maryann E. and Yu, Zeyun and Thor, Andrea and Doi, Masahiro and Holst, Michael J. and Ellisman, Mark H. and Hoshijima, Masahiko}, citeulike-article-id = {4537471}, citeulike-linkout-0 = {http://dx.doi.org/10.1242/jcs.028175}, citeulike-linkout-1 = {http://jcs.biologists.org/cgi/content/abstract/122/7/1005}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/19295127}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=19295127}, day = {1}, doi = {10.1242/jcs.028175}, journal = {J Cell Sci}, keywords = {3d, calcium, cardiac, channel, cluster, electron, microscopy, receptor, ryanodine, ryr}, month = {April}, number = {7}, pages = {1005--1013}, posted-at = {2009-05-18 11:23:47}, priority = {2}, title = {Three-dimensional electron microscopy reveals new details of membrane systems for Ca2+ signaling in the heart}, url = {http://dx.doi.org/10.1242/jcs.028175}, volume = {122}, year = {2009} }

TY - JOUR ID - citeulike:4537471 L3 - citeulike-article-id:4537471 N2 - In the current study, the three-dimensional (3D) topologies of dyadic clefts and associated membrane organelles were mapped in mouse ventricular myocardium using electron tomography. The morphological details and the distribution of membrane systems, including transverse tubules (T-tubules), junctional sarcoplasmic reticulum (SR) and vicinal mitochondria, were determined and presumed to be crucial for controlling cardiac Ca2+ dynamics. The geometric complexity of T-tubules that varied in diameter with frequent branching was clarified. Dyadic clefts were intricately shaped and remarkably small (average 4.39x105 nm3, median 2.81x105 nm3). Although a dyadic cleft of average size could hold maximum 43 ryanodine receptor (RyR) tetramers, more than one-third of clefts were smaller than the size that is able to package as many as 15 RyR tetramers. The dyadic clefts were also adjacent to one another (average end-to-end distance to the nearest dyadic cleft, 19.9 nm) and were distributed irregularly along T-tubule branches. Electron-dense structures that linked membrane organelles were frequently observed between mitochondrial outer membranes and SR or T-tubules. We, thus, propose that the topology of dyadic clefts and the neighboring cellular micro-architecture are the major determinants of the local control of Ca2+ in the heart, including the establishment of the quantal nature of SR Ca2+ releases (e.g. Ca2+ sparks). 10.1242/jcs.028175 IS - 7 JF - J Cell Sci EP - 1013 TI - Three-dimensional electron microscopy reveals new details of membrane systems for Ca2+ signaling in the heart VL - 122 SP - 1005 KW - 3d KW - calcium KW - cardiac KW - channel KW - cluster KW - electron KW - microscopy KW - receptor KW - ryanodine KW - ryr AU - Hayashi, Takeharu AU - Martone, Maryann AU - Yu, Zeyun AU - Thor, Andrea AU - Doi, Masahiro AU - Holst, Michael AU - Ellisman, Mark AU - Hoshijima, Masahiko PY - 2009/04/01/ UR - http://dx.doi.org/10.1242/jcs.028175 ER -