کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1984804 1539966 2008 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Investigations of the potential effects of phosphorylation of the MWFE and ESSS subunits on complex I activity and assembly
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Investigations of the potential effects of phosphorylation of the MWFE and ESSS subunits on complex I activity and assembly
چکیده انگلیسی

There have been several reports on the phosphorylation of various subunits of NADH-ubiquinone oxidoreductase (complex I) in mammalian mitochondria. The effects of phosphorylation on assembly or activity of these subunits have not been investigated directly. The cAMP-dependent phosphorylation of the MWFE and ESSS subunits in isolated bovine heart mitochondria has been recently reported. We have investigated the significance of potential phosphorylation of these two subunits in complex I assembly and function by mutational analysis of the phosphorylation sites. Chinese hamster mutant cell lines missing either the MWFE or the ESSS subunits were transfected and complemented with the corresponding wild type and mutant cDNAs made by site-directed mutagenesis. In MWFE the serine 55 was substituted by alanine, glutamate, glutamine, and aspartate (S55A, S55E, S55Q, and S55D, respectively). The glutamate substitutions might be expected to mimic the phosphorylated state of the protein. With the exception of the MWFE(S55A) mutant protein the assembly of complex I was completely blocked, and no activity could be detected. Various substitutions in the ESSS protein (S2A, S2E, S8A, S8E, T21A, T21E, S30A, S30E) appeared to cause lower levels of mature protein and a significantly reduced complex I activity measured polarographically. The ESSS (S2/8A) double mutant protein caused a complete failure to assemble. These mutational analyses suggest that if phosphorylation occurs in vivo, the effects on complex I activity are significant.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The International Journal of Biochemistry & Cell Biology - Volume 40, Issue 3, 2008, Pages 447–460
نویسندگان
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