| Autor: |
Takahashi, Koui, Shimada, Ken-Ichiro, Ahn, Dong-Hyun, Ji, Jung-Ryong |
| Zdroj: |
Journal of Muscle Research & Cell Motility; May2001, Vol. 22 Issue 4, p353-360, 8p |
| Abstrakt: |
The existence of lipids in Z-discs of the vertebrate skeletal muscle was suggested by the results of microscopy using rhodamine 6G reagent, a fluorescent probe. After removal of lipids by treatment of myofibrils with 0.5% Trition X-100, intact configurations of Z-filaments composed of α-actinin were clearly visible under an electron microscope. These findings indicated that lipids were amorphous-matrix materials of the Z-disc. Lipids were proved to be the main component of Z-discs by their extraction from I-Z-I brushes with a mixture of methanol and chloroform and by analysing them. The total amount of lipids in Z-discs exceeded that of α-actinin and varied from 2.4 to 7.1 g per 100 g of myofibrillar proteins depending on the phenotype of skeletal muscle. The sum of the amounts of lipids and α-actinin was 4.5 g per 100 g of myofibrillar proteins in chicken pectoralis profundus muscle (fast type), while it was 10.1 g in chicken soleus muscle (slow type). Lipid classes were phospholipids, triacylglycerols, cholesterol and free fatty acids. Since the lipids extracted from I-Z-I brushes were hardly contaminated with those from the sarcoplasmic reticulum and mitochondoria, their amounts and classes were considered to be characteristic of Z-discs. The lipids probably cement neighbouring Z-filaments electrostatically, reinforce the Z-disc structure, and play an important role in the force transmission of skeletal muscle myofibrils. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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