Linking Ras to myosin function: RasGEF Q, a Dictyostelium exchange factor for RasB, affects myosin II functions.
Linking Ras to myosin function: RasGEF Q, a Dictyostelium exchange factor for RasB, affects myosin II functions.
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将 Ras 与肌球蛋白功能联系起来:RasGEF Q 是 RasB 的盘基网柄菌交换因子,影响肌球蛋白 II 功能。
DOI:
10.1083/jcb.200710111
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发表时间:
2008
期刊:
影响因子:
--
通讯作者:
Noegel,AngelikaA
中科院分区:
文献类型:
--
作者:
Mondal,Subhanjan;Bakthavatsalam,Deenadayalan;Steimle,Paul;Gassen,Berthold;Rivero,Francisco;Noegel,AngelikaA
The actin cytoskeleton is composed of actin, myosin, and several proteins that bind to them and play crucial roles in cell motility, cytokinesis, phagocytosis, and intracellular transport processes (Cooper, 1991; Matsumura, 2005). Coordinated cell movement requires protrusive forces generated by polymerization of actin filaments at the leading edge and contractile forces via myosin motors at the rear of a cell. Myosin II, the conventional two-headed myosin, is also the primary motor protein required for cytokinesis in eukaryotes. Dictyostelium discoideum cells lacking MhcA show a plethora of defects, which include cytokinesis defect in suspension but undergoing cytokinesis when grown on a solid support by a “tractionmediated” mechanism (De Lozanne and Spudich, 1987). These correspond to the localization of myosin at the contractile ring (cleavage furrow) during cytokinesis. MhcA J cells have a decreased chemotactic efficiency caused by reduction in cell polarity and an inability to suppress lateral pseudopods and retract the uropod (Wessels and Soll, 1990; Wessels et al., 1988). They also have a developmental defect, halting the developmental process shortly after cells have aggregated. The regulation of myosin II appears to differ between higher and lower eukaryotes.In D. discoideum phosphorylation of myosin takes place at three threonine residues in the tail region by myosin II heavy chain kinases (MHCKs)(Luck-Vielmetter et al., 1990; Vaillancourt et al., 1988). P hosphorylated myosin is inactive and does not assemble into filaments, whereas unphosphorylated myosin II can spontaneously assemble into bipolar filaments. It is only these filaments that perform cellular myosin II functions (Egelhoff et al., 1993). Significant knowledge about the function of myosin II regulation has been derived from mutant myosin IIs: 3XALA myosin, where the three phosphorylatable threonines have been mutated to alanine, rendering it a poor substrate for MHCKs; and 3XASP myosin, where the three threonines were replaced by aspartate, mimicking the phosphorylated state. 3XALA myosin mutants show significant myosin overassembly in cytoskeletal fractions and form stable myosin II filaments, which accumulate
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DOI:
--
发表时间:
1981
期刊:
Biochimica et Biophysica Acta
影响因子:
--
作者:
M. Blondelet;P. Brachet
通讯作者:
P. Brachet
影响因子:
64.5
作者:
P. Schaap;Mei Wang
通讯作者:
Mei Wang
影响因子:
2.7
作者:
R. P. Yeh;F. Chan;M. B. Coukell
通讯作者:
M. B. Coukell
DOI:
10.1016/s0021-9258(19)40919-8
发表时间:
1975
期刊:
The Journal of biological chemistry
影响因子:
--
作者:
C. Klein
通讯作者:
C. Klein
影响因子:
5.3
作者:
W. Nellen;Colleen Silan
通讯作者:
Colleen Silan