Differences in myofilament calcium sensitivity in rat psoas fibers reconstituted with troponin T isoforms containing the alpha- and beta-exons.
Differences in myofilament calcium sensitivity in rat psoas fibers reconstituted with troponin T isoforms containing the alpha- and beta-exons.
复制标题
用含有 α 和 β 外显子的肌钙蛋白 T 同种型重建的大鼠腰肌纤维中肌丝钙敏感性的差异。
DOI：
10.1016/j.abb.2006.06.008
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发表时间：
2006
影响因子：
3.9
通讯作者：
Chandra,Murali
中科院分区：
文献类型：
--
作者：
Gallon,ClareE;Tschirgi,MatthewL;Chandra,Murali
快速骨骼肌肌钙蛋白T（fsTnT）的羧基端是高度保守的。然而，fsTnT基因中外显子16和17的互斥剪接导致α-或β-fsTnT同种型的表达。α-同种型仅在成人快速骨骼肌中表达，而β-同种型在整个肌肉发育过程中以不同的量表达。用含有任一种fsTnT异构体的大鼠快速骨骼肌钙蛋白复合物重建清洁剂皮肤的成年大鼠腰肌纤维表明，用α-fsTnT重建比用β-fsTnT重建导致更大的肌丝Ca 2+敏感性，而不改变Ca 2+激活的最大张力、ATP酶活性或张力成本。观察到的肌丝Ca 2+敏感性的亚型特异性差异可能是由于细丝调节单元从关闭状态转变为打开状态的变化，可能是由于fsTnT的C-末端与肌钙蛋白I和/或C的相互作用改变。
The carboxy terminus of fast skeletal muscle troponin T (fsTnT) is highly conserved. However, mutually exclusive splicing of exons 16 and 17 in the fsTnT gene results in the expression of either the α- or β-fsTnT isoform. The α-isoform is expressed only in adult fast skeletal muscle, whereas the β-isoform is expressed in varying quantities throughout muscle development. Reconstitution of detergent-skinned adult rat psoas muscle fibers with rat fast skeletal troponin complexes containing either fsTnT isoform demonstrated that reconstitution with α-fsTnT resulted in greater myofilament Ca2+sensitivity than reconstitution with β-fsTnT, without changes to Ca2+-activated maximal tension, ATPase activity or tension cost. The observed isoform-specific differences in myofilament Ca2+sensitivity may be due to changes in the transition of the thin-filament regulatory unit from the off to the on state, possibly due to altered interactions of the C-terminus of fsTnT with troponins I and/or C.