A new twist in cardiac muscle:dislocated and helicoid arrangements of myofibrillar z-disks in mammalian ventricular myocytes

Jayasinghe, Isuru D, Crossman, David J, Soeller, Christian and Cannell, Mark B (2010) A new twist in cardiac muscle:dislocated and helicoid arrangements of myofibrillar z-disks in mammalian ventricular myocytes. Journal of Molecular and Cellular Cardiology, 48 (5). pp. 964-71. ISSN 1095-8584

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Using deconvolved confocal microscopy of fluorescently labeled markers for z-disks, t-tubules and ryanodine receptors, we have examined sarcomere organization in cardiac myocytes from rat, rabbit and human. We show that sarcomeres exhibit dislocations in registration and occasionally more complex helicoidal topology. This organization was present at both slack ( approximately 1.8 microm) and long sarcomere lengths ( approximately 2.2 microm). Misregistrations in z-disks persisted over 15-20 sarcomere lengths and appeared to arise primarily from variations in fiber direction; particularly as myofibrils pass around nuclei. In addition, myofibrils twist along the cell length. T-tubules generally follow the sarcomere z-disks although additional elements bridging adjacent myofibrils and along the length of the myofibril are present to varying degrees in all cells. Ryanodine receptors (the sarcoplasmic reticulum Ca(2+) release channel) are generally located within 250 nm of the local plane containing t-tubules and z-disks, but a small fraction ( approximately 2%) is found on longitudinal elements of the t-system between z-disks. The results are discussed with respect to the possible role(s) of such complex z-disk organization and z-disk dislocations in the maintenance of cell structure and sarcomere assembly. In addition, the non-planar organization of z-disks may be important in the propagation of local Ca(2+) waves which may have a useful role in helping maintain the uniformity of sarcomere activation in the presence of t-tubule remodeling.

Item Type: Article
Additional Information: Copyright (c) 2009 Elsevier Ltd. All rights reserved.
Uncontrolled Keywords: animals,cells, cultured,heart ventricles,humans,immunohistochemistry,microscopy, confocal,myocytes, cardiac,myofibrils,rabbits,rats,rats, wistar,ryanodine receptor calcium release channel,sarcomeres
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups: Faculty of Medicine and Health Sciences > Research Groups > Norwich Clinical Trials Unit
Depositing User: Pure Connector
Date Deposited: 06 Jan 2014 14:58
Last Modified: 24 Oct 2022 05:34
URI: https://ueaeprints.uea.ac.uk/id/eprint/46195
DOI: 10.1016/j.yjmcc.2009.12.012

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