The mammalian skeletal muscle DHPR has larger Ca(2+) conductance and is phylogenetically ancient to the early ray-finned fish sterlet (Acipenser ruthenus).
The mammalian skeletal muscle DHPR has larger Ca(2+) conductance and is phylogenetically ancient to the early ray-finned fish sterlet (Acipenser ruthenus).
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DOI：
10.1016/j.ceca.2016.10.002
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发表时间：
2017-01
期刊：
影响因子：
4
通讯作者：
Grabner M
中科院分区：
文献类型：
--
作者：
Schrötter K;Dayal A;Grabner M
脊椎动物骨骼肌中的L钙通道或二氢吡啶受体负责感受肌膜的去极化，并通过构象偶联将这一信号传递到肌浆钙释放通道RyR1，从而启动肌肉收缩。在这个兴奋-收缩(EC)耦合过程中，有一种缓慢的钙电流通过哺乳动物的DHPR，而这在真鱼中是完全缺失的。与骨骼肌EC偶联仍然依赖于钙诱导的钙释放(CICR)的祖先进化阶段不同，哺乳动物(构象)EC偶联过程中DHPR的钙电导可能被保留为进化的残留物(残留)。在这里，我们想要检验的假设是，由于后CICR物种缺乏进化压力，骨骼肌DHPR钙电导率随着进化的进展而逐渐降低。有趣的是，我们鉴定了早期鳍鱼(Acipenser Ruthenus)的DHPR位于哺乳动物DHPR的系统发育之上，而DHPR保留了很强的钙离子电导，而低于Euteleost斑马鱼DHPR，后者完全失去了钙离子的电导。值得注意的是，我们的结果显示，与兔相比，胸腺DHPR仍然保持了钙离子的电导，但电流显著减少。这一下降是由于与斑马鱼相似的DHPR膜表达降低以及通道开放概率(Po)降低所致。在这两种鱼中，较低的DHPR表达密度被较高的DHPR-RyR1偶联效率部分补偿。斑马鱼和其他真脊椎动物中Po的完全丧失可能是基于硬骨鱼特有的第三轮基因组复制(Ts3R)。Ts3R进入了两个骨骼肌DHPR亚型的出现，最终与Eutelost分支的辐射一起，完全失去了Po。
The L-type Ca2+ channel or dihydropyridine receptor (DHPR) in vertebrate skeletal muscle is responsible for sensing sarcolemmal depolarizations and transducing this signal to the sarcoplasmic Ca2+ release channel RyR1 via conformational coupling to initiate muscle contraction. During this excitation-contraction (EC) coupling process there is a slow Ca2+ current through the mammalian DHPR which is fully missing in euteleost fishes. In contrast to ancestral evolutionary stages where skeletal muscle EC coupling is still depended on Ca2+-induced Ca2+-release (CICR), it is possible that the DHPR Ca2+ conductivity during mammalian (conformational) EC coupling was retained as an evolutionary remnant (vestigiality). Here, we wanted to test the hypothesis that due to the lack of evolutionary pressure in post-CICR species skeletal muscle DHPR Ca2+ conductivity gradually reduced as evolution progressed. Interestingly, we identified that the DHPR of the early ray-finned fish sterlet (Acipenser ruthenus) is phylogenetically positioned above the mammalian rabbit DHPR which retained robust Ca2+ conductivity, but below the euteleost zebrafish DHPR which completely lost Ca2+ conductivity. Remarkably, our results revealed that sterlet DHPR still retained the Ca2+ conductivity but currents are significantly reduced compared to rabbit. This decrease is due to lower DHPR membrane expression similar to zebrafish, as well as due to reduced channel open probability (Po). In both these fish species the lower DHPR expression density is partially compensated by higher efficacy of DHPR-RyR1 coupling. The complete loss of Po in zebrafish and other euteleost species was presumably based on the teleost specific 3rd round of genome duplication (Ts3R). Ts3R headed into the appearance of two skeletal muscle DHPR isoforms which finally, together with the radiation of the euteleost clade, fully lost the Po.
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DOI：
10.1098/rspb.1994.0026
发表时间：
1994-02-22
影响因子：
4.7
作者：
INOUE, I;TSUTSUI, I;BROWN, ER
通讯作者：
BROWN, ER
影响因子：
56.9
作者：
NABAUER, M;CALLEWAERT, G;MORAD, M
通讯作者：
MORAD, M
DOI：
10.1016/0005-2728(72)90194-6
发表时间：
1972-01-01
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
ARMSTRONG, CM;BEZANILLA, FM;HOROWICZ, P
通讯作者：
HOROWICZ, P
影响因子：
3.8
作者：
BEAM, KG;KNUDSON, CM
通讯作者：
KNUDSON, CM
影响因子：
3.4
作者：
Franzini-Armstrong, C;Protasi, F;Ramesh, V
通讯作者：
Ramesh, V