کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1985012 1539993 2005 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Cellular signals activating muscle proteolysis in chronic kidney disease: A two-stage process
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Cellular signals activating muscle proteolysis in chronic kidney disease: A two-stage process
چکیده انگلیسی

Muscle atrophy is a prominent feature of catabolic conditions and in animal models of these conditions there is accelerated muscle proteolysis that is dependent on the ubiquitin–proteasome system. However, ubiquitin system cannot degrade actomyosin or myofibrils even though it rapidly degrades actin or myosin. We identified caspase-3 as the initial and potentially rate-limiting proteolytic step that cleaves actomyosin/myofibrils. In rodent models of catabolic conditions, we find that caspase-3 is activated to cleave muscle proteins and actomyosin to fragments that are rapidly degraded by the ubiquitin system. This initial proteolytic step in muscle can be recognized because it leaves a footprint of a characteristic 14-kDa actin band. Stimulation of caspase-3 activity depends on activation of phosphatidylinositol 3-kinase. When we suppressed this enzyme in muscle cells, protein breakdown increased as did the expression of caspase-3. In addition, there was increased expression of E3-ubiquitin-conjugating enzymes that are involved in muscle proteolysis, atrogin-1/MAFbx and MuRF1. Thus, when phosphatidylinositol 3-kinase activity is low in muscle cells or rat muscle, both caspase-3 and the ubiquitin–proteasome system are stimulated to degrade protein. Additional investigations will be needed to define the cell signaling processes that activate muscle proteolysis in uremia and catabolic conditions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The International Journal of Biochemistry & Cell Biology - Volume 37, Issue 10, October 2005, Pages 2147–2155
نویسندگان
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