TY - JOUR AB - The Z-band in vertebrate striated muscle crosslinks actin filaments of opposite polarity from adjoiningsarcomeres and transmits tension along myofibrils during muscular contraction. It is also the location of anumber of proteins involved in signalling and myofibrillogenesis; mutations in these proteins lead to myopathies.Understanding the high-resolution structure of the Z-band will help us understand its role in muscle contractionand the role of these proteins in the function of muscle. The appearance of the Z-band in transverse-sectionelectron micrographs typically resembles a small-square lattice or a basketweave appearance. In longitudinalsections, the Z-band width varies more with muscle type than species: slow skeletal and cardiac muscles havewider Z-bands than fast skeletal muscles. As the Z-band is periodic, Fourier methods have previously beenused for three-dimensional structural analysis. To cope with variations in the periodic structure of the Z-band, wehave used subtomogram averaging of tomograms of rat cardiac muscle in which subtomograms are extractedand compared and similar ones are averaged. We show that the Z-band comprises four to six layers of links,presumably α-actinin, linking antiparallel overlapping ends of the actin filaments from the adjoining sarcomeres.The reconstruction shows that the terminal 5–7 nm of the actin filaments within the Z-band is devoid of anyα-actinin links and is likely to be the location of capping protein CapZ. AU - Luther,PK AU - Burgoyne,T AU - Morris,E DO - 10.1016/j.jmb.2015.08.018 EP - 3537 PY - 2015/// SN - 1089-8638 SP - 3527 TI - Three-Dimensional Structure of Vertebrate Muscle Z-Band: The Small-Square Lattice Z-Band in Rat Cardiac Muscle T2 - Journal of Molecular Biology UR - http://dx.doi.org/10.1016/j.jmb.2015.08.018 UR - http://hdl.handle.net/10044/1/34327 VL - 427 ER -