Regulation of the actin-activated MgATPase activity of Acanthamoeba myosin II by phosphorylation of serine 639 in motor domain loop 2

The study tested the hypothesis that estrogen controls epithelial paracellular resistance through modulation of myosin. The objective was to understand how estrogen modulates nonmuscle myosin-II-B (NMM-II-B), the main component of the cortical actomyosin in human epithelial cervical cells. Experiments used human cervical epithelial cells CaSki as a model, and end points were NMM-II-B phosphorylation, filamentation, and MgATPase activity. The results were as follows: 1) treatment with estrogen increased phosphorylation and MgATPase activity and decreased NMM-II-B filamentation; 2) estrogen effects could be blocked by antisense nucleotides for the estrogen receptor-α and by ICI-182,780, tamoxifen, and the casein kinase-II (CK2) inhibitor, 5,6-dichloro-1-β-(D)-ribofuranosylbenzimidazole and attenuated by AG1478 and PD98059 (inhibitors of epithelial growth factor receptor and ERK/MAPK) but not staurosporine [blocker of protein kinase C (PKC)]; 3) treatments with the PKC activator sn-1,2-dioctanoyl diglyceride induced biphasic effect on NMM-II-B MgATPase activity: an increase at 1 nm to 1 μm and a decrease in activity at more than 1 μm; 4) sn-1,2-dioctanoyl diglyceride also decreased NMM-II-B filamentation in a monophasic and saturable dose dependence (EC50 1–10 μm); 5) when coincubated directly with purified NMM-II-B filaments, both CK2 and PKC decreased filamentation and increased MgATPase activity; 6) assays done on disassembled NMM-II-B filaments showed MgATPase activity in filaments obtained from estrogen-treated cells but not estrogen-depleted cells; and 7) incubations in vitro with CK2, but not PKC, facilitated MgATPase activity, even in disassembled NMM-II-B filaments. The results suggest that estrogen, in an effect mediated by estrogen receptor-α and CK2 and involving the epithelial growth factor receptor and ERK/MAPK cascades, increases NMM-II-B MgATPase activity independent of NMM-II-B filamentation status.

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Engineering lysine reactivity as a conformational sensor in the Dictyostelium myosin II motor domain

Journal of Muscle Research and Cell Motility ◽

10.1023/b:jure.0000021352.80800.b8 ◽

2004 ◽

Vol 25 (1) ◽

pp. 95-102 ◽

Cited By ~ 2

Author(s):

Mihály Kovács ◽

Judit Tóth ◽

András Málnási-Csizmadia ◽

Clive R. Bagshaw ◽

László Nyitray

Keyword(s):

Myosin Ii ◽

Motor Domain ◽

Dictyostelium Myosin

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Cytokinesis Depends on the Motor Domains of Myosin-II in Fission Yeast but Not in Budding Yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e05-07-0601 ◽

2005 ◽

Vol 16 (11) ◽

pp. 5346-5355 ◽

Cited By ~ 77

Author(s):

Matthew Lord ◽

Ellen Laves ◽

Thomas D. Pollard

Keyword(s):

Atpase Activity ◽

Fission Yeast ◽

Mechanism Of Action ◽

Budding Yeast ◽

Myosin Ii ◽

Cellular Function ◽

Motor Domain ◽

Actin Binding ◽

Contractile Ring ◽

Head Domain

Budding yeast possesses one myosin-II, Myo1p, whereas fission yeast has two, Myo2p and Myp2p, all of which contribute to cytokinesis. We find that chimeras consisting of Myo2p or Myp2p motor domains fused to the tail of Myo1p are fully functional in supporting budding yeast cytokinesis. Remarkably, the tail alone of budding yeast Myo1p localizes to the contractile ring, supporting both its constriction and cytokinesis. In contrast, fission yeast Myo2p and Myp2p require both the catalytic head domain as well as tail domains for function, with the tails providing distinct functions ( Bezanilla and Pollard, 2000 ). Myo1p is the first example of a myosin whose cellular function does not require a catalytic motor domain revealing a novel mechanism of action for budding yeast myosin-II independent of actin binding and ATPase activity.

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A Point Mutation in the Motor Domain of Nonmuscle Myosin II-B Impairs Migration of Distinct Groups of Neurons

Molecular Biology of the Cell ◽

10.1091/mbc.e03-11-0836 ◽

2004 ◽

Vol 15 (6) ◽

pp. 2568-2579 ◽

Cited By ~ 71

Author(s):

Xuefei Ma ◽

Sachiyo Kawamoto ◽

Yoshinobu Hara ◽

Robert S. Adelstein

Keyword(s):

Neuronal Migration ◽

Granule Cells ◽

Myosin Ii ◽

Active Role ◽

Motor Domain ◽

Mutant Mice ◽

Single Amino Acid ◽

Nonmuscle Myosin ◽

Abnormal Gait ◽

Homozygous Mutant

We generated mice harboring a single amino acid mutation in the motor domain of nonmuscle myosin heavy chain II-B (NMHC II-B). Homozygous mutant mice had an abnormal gait and difficulties in maintaining balance. Consistent with their motor defects, the mutant mice displayed an abnormal pattern of cerebellar foliation. Analysis of the brains of homozygous mutant mice showed significant defects in neuronal migration involving granule cells in the cerebellum, the facial neurons, and the anterior extramural precerebellar migratory stream, including the pontine neurons. A high level of NMHC II-B expression in these neurons suggests an important role for this particular isoform during neuronal migration in the developing brain. Increased phosphorylation of the myosin II regulatory light chain in migrating, compared with stationary pontine neurons, supports an active role for myosin II in regulating their migration. These studies demonstrate that NMHC II-B is particularly important for normal migration of distinct groups of neurons during mouse brain development.

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Functional expression of a chimeric myosin-containing motor domain of Chara myosin and neck and tail domains of Dictyostelium myosin II 1 1Edited by J. Karn

Journal of Molecular Biology ◽

10.1006/jmbi.2001.4883 ◽

2001 ◽

Vol 311 (3) ◽

pp. 461-466 ◽

Cited By ~ 10

Author(s):

Taku Kashiyama ◽

Kohji Ito ◽

Keiichi Yamamoto

Keyword(s):

Myosin Ii ◽

Functional Expression ◽

Motor Domain ◽

Dictyostelium Myosin

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Chimeras of Dictyostelium myosin II head and neck domains with Acanthamoeba or chicken smooth muscle myosin II tail domain have greatly increased and unregulated actin-dependent MgATPase activity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.230441497 ◽

2000 ◽

Vol 97 (23) ◽

pp. 12553-12558 ◽

Cited By ~ 6

Author(s):

X. Liu ◽

S. Shu ◽

R. A. Yamashita ◽

Y. Xu ◽

E. D. Korn

Keyword(s):

Smooth Muscle ◽

Head And Neck ◽

Myosin Ii ◽

Smooth Muscle Myosin ◽

Tail Domain ◽

Dictyostelium Myosin ◽

Muscle Myosin ◽

Mgatpase Activity

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The prepower stroke conformation of myosin V

The Journal of Cell Biology ◽

10.1083/jcb.200208172 ◽

2002 ◽

Vol 159 (6) ◽

pp. 983-991 ◽

Cited By ~ 96

Author(s):

Stan Burgess ◽

Matt Walker ◽

Fei Wang ◽

James R. Sellers ◽

Howard D. White ◽

...

Keyword(s):

Electron Microscopy ◽

Image Processing ◽

Thermal Energy ◽

Single Particle ◽

Particle Image ◽

Myosin Ii ◽

Motor Domain ◽

Axial Position ◽

Myosin V ◽

Similar Conformation

eW have used electron microscopy and single-particle image processing to study head conformation in myosin V molecules. We find that in the presence of ATP, many heads have a sharply angled conformation that is rare in its absence. The sharply angled conformation is similar to a myosin II atomic structure proposed to mimic the prepower stroke state. The leading head in molecules attached to actin by both heads has a similar conformation, but is also sharply angled in a second plane by tethering through the trail head. The lead head lever joins the motor domain ∼5 nm axially from where it joins the trail motor. These positions locate the converter subdomain and show the lead motor is in the prepower stroke conformation. Tethering by the trail head places the lead head motor domain at the correct axial position along the actin for binding, but at the wrong orientation. Attachment is achieved either by bending the lead head lever throughout its length or at the pliant point. The microscopy shows that most of the walking stride is produced by changes in lever angle brought about by converter movement, but is augmented by distortion produced by thermal energy.

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