National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01-GM030598
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35-GM139616
米国
National Institutes of Health/National Center for Research Resources (NIH/NCRR)
S10RR025080
米国
National Institutes of Health/Office of the Director
S10OD018142
米国
American Heart Association
15PRE25090150
米国
American Heart Association
20PRE35120273
米国
引用
ジャーナル: J Muscle Res Cell Motil / 年: 2023 タイトル: The cryo-EM 3D image reconstruction of isolated Lethocerus indicus Z-discs. 著者: Fatemeh Abbasi Yeganeh / Corinne Summerill / Zhongjun Hu / Hamidreza Rahmani / Dianne W Taylor / Kenneth A Taylor / 要旨: The Z-disk of striated muscle defines the ends of the sarcomere, which repeats many times within the muscle fiber. Here we report application of cryoelectron tomography and subtomogram averaging to Z- ...The Z-disk of striated muscle defines the ends of the sarcomere, which repeats many times within the muscle fiber. Here we report application of cryoelectron tomography and subtomogram averaging to Z-disks isolated from the flight muscles of the large waterbug Lethocerus indicus. We use high salt solutions to remove the myosin containing filaments and use gelsolin to remove the actin filaments of the A- and I-bands leaving only the thin filaments within the Z-disk which were then frozen for cryoelectron microscopy. The Lethocerus Z-disk structure is similar in many ways to the previously studied Z-disk of the honeybee Apis mellifera. At the corners of the unit cell are positioned trimers of paired antiparallel F-actins defining a large solvent channel, whereas at the trigonal positions are positioned F-actin trimers converging slowly towards their (+) ends defining a small solvent channel through the Z-disk. These near parallel F-actins terminate at different Z-heights within the Z-disk. The two types of solvent channel in Lethocerus are similar in size compared to those of Apis which are very different in size. Two types of α-actinin crosslinks were observed between oppositely oriented actin filaments. In one of these, the α-actinin long axis is almost parallel to the F-actins it crosslinks. In the other, the α-actinins are at a small but distinctive angle with respect to the crosslinked actin filaments. The utility of isolated Z-disks for structure determination is discussed.