کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5504272 | 1536271 | 2017 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Functional significance of C-terminal mobile domain of cardiac troponin I
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کلمات کلیدی
cTnIN,N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acidBDMcTNTEGTADTTBES2,3-Butanedione monoxime - 2،3-Butanedione monoximeethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid - اتیلن گلیکول بیس (β-آمینویل اتر) -N، N، N '، N'-tetraacetic اسیدcTnC - ایتناLDA - تخصیص پنهان دیریکلهTroponin - تروپونینcardiac troponin C - تروپونین C قلبcardiac troponin T - تروپونین T قلبdithiothreitol - دیتیوتریتولCross-bridge kinetics - سینتیک عبور پلSarcomere length - طول سارکومرcardiac troponin I - قلب تروپونین I
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Ca2+-regulation of cardiac contractility is mediated through the troponin complex, which comprises three subunits: cTnC, cTnI, and cTnT. As intracellular [Ca2+] increases, cTnI reduces its binding interactions with actin to primarily interact with cTnC, thereby enabling contraction. A portion of this regulatory switching involves the mobile domain of cTnI (cTnI-MD), the role of which in muscle contractility is still elusive. To study the functional significance of cTnI-MD, we engineered two cTnI constructs in which the MD was truncated to various extents: cTnI(1-167) and cTnI(1-193). These truncations were exchanged for endogenous cTnI in skinned rat papillary muscle fibers, and their influence on Ca2+-activated contraction and cross-bridge cycling kinetics was assessed at short (1.9 μm) and long (2.2 μm) sarcomere lengths (SLs). Our results show that the cTnI(1-167) truncation diminished the SL-induced increase in Ca2+-sensitivity of contraction, but not the SL-dependent increase in maximal tension, suggesting an uncoupling between the thin and thick filament contributions to length dependent activation. Compared to cTnI(WT), both truncations displayed greater Ca2+-sensitivity and faster cross-bridge attachment rates at both SLs. Furthermore, cTnI(1-167) slowed MgADP release rate and enhanced cross-bridge binding. Our findings imply that cTnI-MD truncations affect the blocked-to closed-state transition(s) and destabilize the closed-state position of tropomyosin.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Archives of Biochemistry and Biophysics - Volume 634, 15 November 2017, Pages 38-46
Journal: Archives of Biochemistry and Biophysics - Volume 634, 15 November 2017, Pages 38-46
نویسندگان
Nazanin Bohlooli Ghashghaee, Bertrand C.W. Tanner, Wen-Ji Dong,