scholarly journals Type II Myosin Heavy Chain Encoded by the myo2 Gene Composes the Contractile Ring during Cytokinesis in Schizosaccharomyces pombe

1997 ◽  
Vol 137 (6) ◽  
pp. 1309-1319 ◽  
Author(s):  
Chikako Kitayama ◽  
Asako Sugimoto ◽  
Masayuki Yamamoto
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Coiled Coil ◽  
Yeast Cells ◽  
Type Ii ◽  
Contractile Ring ◽  
Iq Motif ◽  
Multinucleated Cells ◽  
Type Ii Myosin

We cloned the myo2 gene of Schizosaccharomyces pombe, which encodes a type II myosin heavy chain, by virtue of its ability to promote diploidization in fission yeast cells. The myo2 gene encodes 1,526 amino acids in a single open reading frame. Myo2p shows homology to the head domains and the coiledcoil tail of the conventional type II myosin heavy chain and carries putative binding sites for ATP and actin. It also carries the IQ motif, which is a presumed binding site for the myosin light chain. However, Myo2p apparently carries only one IQ motif, while its counterparts in other species have two. There are nine proline residues, which should break α-helix, in the COOH-terminal coiled-coil region of Myo2p. Thus, Myo2p is rather unusual as a type II myosin heavy chain. Disruption of myo2 inhibited cell proliferation. myo2Δ cells showed normal punctate distribution of interphase actin, but they produced irregular actin rings and septa and were impaired in cell separation. Overproduction of Myo2p was also lethal, apparently blocking actin relocation. Nuclear division proceeded without actin ring formation and cytokinesis in cells overexpressing Myo2p, giving rise to multinucleated cells with dumbbell morphology. Analysis using tagged Myo2p revealed that Myo2p colocalizes with actin in the contractile ring, suggesting that Myo2p is a component of the ring and responsible for its contraction. Furthermore, genetic evidence suggested that the acto–myosin system may interact with the Ras pathway, which regulates mating and the maintenance of cell morphology in S. pombe.

Identification of Myo3, a second type-II myosin heavy chain in the fission yeast Schizosaccharomyces pombe

FEBS Letters ◽  
1997 ◽  
Vol 420 (2-3) ◽  
pp. 161-166 ◽  
Author(s):  
Fumio Motegi ◽  
Kentaro Nakano ◽  
Chikako Kitayama ◽  
Masayuki Yamamoto ◽  
Issei Mabuchi
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Myosin Heavy Chain ◽  
Fission Yeast ◽  
Heavy Chain ◽  
Type Ii ◽  
Type Ii Myosin

Relationships between maximal strength, muscle size, and myosin heavy chain isoform composition and postactivation potentiation

2016 ◽  
Vol 41 (5) ◽  
pp. 491-497 ◽  
Author(s):  
Laurent B. Seitz ◽  
Gabriel S. Trajano ◽  
G. Gregory Haff ◽  
Charles C.L.S. Dumke ◽  
James J. Tufano ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Human Skeletal Muscle ◽  
Knee Extensor ◽  
Type Ii ◽  
Postactivation Potentiation ◽  
Test Protocol ◽  
Extensor Torque ◽  
Type Ii Myosin

The purpose of this study was to examine the relationships between maximal voluntary postactivation potentiation (PAP) and maximal knee extensor torque, quadriceps cross-sectional area (CSA) and volume, and type II myosin heavy chain (MHC) isoform percentage in human skeletal muscle. Thirteen resistance-trained men completed a test protocol consisting of 2 isokinetic knee extensions at 180°·s–1 performed before and 1, 4, 7, and 10 min after the completion of 4 maximal knee extensions at 60°·s–1 (i.e., a conditioning activity (CA)). Magnetic resonance imaging and muscle microbiopsy procedures were completed on separate days to assess quadriceps CSA and volume and MHC isoform content. Maximal voluntary PAP response was assessed as the ratio of the highest knee extensor torques measured before and after the CA. There were large to very large correlations between maximal voluntary PAP response and maximal knee extensor torque (r = 0.62) and quadriceps CSA (r = 0.68) and volume (r = 0.63). Nonetheless, these correlations were not statistically significant after adjusting for the influence of type II MHC percentage using partial correlation analysis. By contrast, the strongest correlation was observed for type II MHC percentage (r = 0.77), and this correlation remained significant after adjusting for the other variables. Maximal voluntary PAP response is strongly correlated with maximal knee extensor torque and quadriceps CSA and volume, but is mostly clearly associated with the type II myosin isoform percentage in human skeletal muscle.

Type II myosin regulatory light chain relieves auto-inhibition of myosin-heavy-chain function

2000 ◽  
Vol 2 (11) ◽  
pp. 855-858 ◽  
Author(s):  
Naweed I. Naqvi ◽  
Kelvin C. Y. Wong ◽  
Xie Tang ◽  
Mohan K. Balasubramanian
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Light Chain ◽  
Regulatory Light Chain ◽  
Myosin Regulatory Light Chain ◽  
Type Ii ◽  
Type Ii Myosin

The yeast type II myosin heavy chain: Analysis of its predicted polypeptide sequence

1991 ◽  
Vol 12 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Frank P. Sweeney ◽  
Michael J. Pocklington ◽  
Elisha Orr
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Type Ii ◽  
Chain Analysis ◽  
Polypeptide Sequence ◽  
Type Ii Myosin

scholarly journals The inv(16) Fusion Protein Associates with Corepressors via a Smooth Muscle Myosin Heavy-Chain Domain

2003 ◽  
Vol 23 (2) ◽  
pp. 607-619 ◽  
Author(s):  
Kristie L. Durst ◽  
Bart Lutterbach ◽  
Tanawan Kummalue ◽  
Alan D. Friedman ◽  
Scott W. Hiebert
Keyword(s):  
Amino Acids ◽  
Smooth Muscle ◽  
Fusion Protein ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Transcriptional Repression ◽  
Coiled Coil ◽  
Smooth Muscle Myosin ◽  
Muscle Myosin ◽  
Repression Domain

ABSTRACT Inversion(16) is one of the most frequent chromosomal translocations found in acute myeloid leukemia (AML), occurring in over 8% of AML cases. This translocation results in a protein product that fuses the first 165 amino acids of core binding factor β to the coiled-coil region of a smooth muscle myosin heavy chain (CBFβ/SMMHC). CBFβ interacts with AML1 to form a heterodimer that binds DNA; this interaction increases the affinity of AML1 for DNA. The CBFβ/SMMHC fusion protein cooperates with AML1 to repress the transcription of AML1-regulated genes. We show that CBFβ/SMMHC contains a repression domain in the C-terminal 163 amino acids of the SMMHC region that is required for inv(16)-mediated transcriptional repression. This minimal repression domain is sufficient for the association of CBFβ/SMMHC with the mSin3A corepressor. In addition, the inv(16) fusion protein specifically associates with histone deacetylase 8 (HDAC8). inv(16)-mediated repression is sensitive to HDAC inhibitors. We propose a model whereby the inv(16) fusion protein associates with AML1 to convert AML1 into a constitutive transcriptional repressor.

scholarly journals Aim44p regulates phosphorylation of Hof1p to promote contractile ring closure during cytokinesis in budding yeast

2014 ◽  
Vol 25 (6) ◽  
pp. 753-762 ◽  
Author(s):  
Dana M. Alessi Wolken ◽  
Joseph McInnes ◽  
Liza A. Pon
Keyword(s):  
Cell Division ◽  
Protein Product ◽  
Ring Closure ◽  
Type Ii ◽  
Contractile Ring ◽  
Double Ring ◽  
Mother And Daughter ◽  
Associated Proteins ◽  
And Function ◽  
Type Ii Myosin

Whereas actomyosin and septin ring organization and function in cytokinesis are thoroughly described, little is known regarding the mechanisms by which the actomyosin ring interacts with septins and associated proteins to coordinate cell division. Here we show that the protein product of YPL158C, Aim44p, undergoes septin-dependent recruitment to the site of cell division. Aim44p colocalizes with Myo1p, the type II myosin of the contractile ring, throughout most of the cell cycle. The Aim44p ring does not contract when the actomyosin ring closes. Instead, it forms a double ring that associates with septin rings on mother and daughter cells after cell separation. Deletion of AIM44 results in defects in contractile ring closure. Aim44p coimmunoprecipitates with Hof1p, a conserved F-BAR protein that binds both septins and type II myosins and promotes contractile ring closure. Deletion of AIM44 results in a delay in Hof1p phosphorylation and altered Hof1p localization. Finally, overexpression of Dbf2p, a kinase that phosphorylates Hof1p and is required for relocalization of Hof1p from septin rings to the contractile ring and for Hof1p-triggered contractile ring closure, rescues the cytokinesis defect observed in aim44∆ cells. Our studies reveal a novel role for Aim44p in regulating contractile ring closure through effects on Hof1p.

scholarly journals A phylogenetic analysis of myosin heavy chain type II sequences corroborates that Acoela and Nemertodermatida are basal bilaterians

2002 ◽  
Vol 99 (17) ◽  
pp. 11246-11251 ◽  
Author(s):  
I. Ruiz-Trillo ◽  
J. Paps ◽  
M. Loukota ◽  
C. Ribera ◽  
U. Jondelius ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Type Ii ◽  
Chain Type

Myosin heavy chain isoforms of human muscle after short-term spaceflight

1995 ◽  
Vol 78 (5) ◽  
pp. 1740-1744 ◽  
Author(s):  
M. Y. Zhou ◽  
H. Klitgaard ◽  
B. Saltin ◽  
R. R. Roy ◽  
V. R. Edgerton ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Space Shuttle ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Rapid Change ◽  
Myosin Heavy Chain Isoforms ◽  
Single Fiber ◽  
Type I ◽  
Type Ii

The influence of microgravity on the myosin phenotype of skeletal muscle fibers in the vastus lateralis of eight crew members was studied before and after 5-day (n = 3) and 11-day (n = 5) spaceflights (space shuttle flights: STS-32, -33 and -34). Single-fiber electrophoresis analyses showed that the proportion of fibers expressing only slow (type I) myosin heavy chain (MHC) in the vastus lateralis was significantly lower after than before 11 days of spaceflight. Although the family of type II MHC isoforms was elevated post- compared with preflight, the distribution among the isoforms of type II MHC was not statistically different. Based on monoclonal and polyclonal antibodies specific for three adult MHC isoforms and single-fiber electrophoresis, approximately 3% of the fibers analyzed coexpressed all three adult MHC isoforms. The results from immunohistochemical staining with two different sets of antibodies indicate a reduction in the percentage of fibers expressing type I MHC as a result of spaceflight. The mean difference, however, was significant only when the fibers were categorized simply as type I or II. These changes appeared to be highly individualized among the astronauts. These results suggest that a rapid change in MHC isoform expression can occur in some muscle fibers after a relatively brief exposure to spaceflight.

Effect of hypothyroidism on myosin heavy chain expression in rat pharyngeal dilator muscles

1992 ◽  
Vol 73 (1) ◽  
pp. 179-187 ◽  
Author(s):  
B. J. Petrof ◽  
A. M. Kelly ◽  
N. A. Rubinstein ◽  
A. I. Pack
Keyword(s):  
Thyroid Hormone ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Hormone Deficiency ◽  
Type I ◽  
Type Ii ◽  
Airway Patency ◽  
Obstructive Sleep ◽  
Type I Fibers ◽  
Fast Twitch

Although the association between hypothyroidism and obstructive sleep apnea is well established, the effect of thyroid hormone deficiency on contractile proteins in pharyngeal dilator muscles responsible for maintaining upper airway patency is unknown. In the present study, the effects of hypothyroidism on myosin heavy chain (MHC) expression were examined in the sternohyoid, geniohyoid, and genioglossus muscles of adult rats (n = 20). The relative proportions of MHC isoforms present were determined using MHC-specific monoclonal antibodies and oligonucleotide probes. All control muscles showed a paucity of type I MHC fibers, with greater than 90% of fibers containing fast-twitch type II MHCs. In the genioglossus muscle, a population of non-IIa non-IIb fast-twitch type II fibers (putatively identified as type IIx MHC fibers) were detected. Hypothyroidism induced significant changes in MHC expression in all muscles studied. In the sternohyoid, type I fibers increased from 6.2 to 16.9%, whereas type IIa fibers increased from 25.9 to 30.7%. Type I fibers in the geniohyoid increased from 1.2 to 12.8%, whereas type IIa fibers increased from 34.1 to 42.7%. The genioglossus showed the smallest relative increase in type I expression but the greatest induction of type IIa MHC. None of the muscles examined demonstrated reinduction of embryonic or neonatal MHC in response to thyroid hormone deficiency. In summary, hypothyroidism alters the MHC profile of pharyngeal dilators in a muscle-specific manner. These changes may play a role in the pathogenesis of obstructive apnea in hypothyroid patients.

scholarly journals Myosin heavy-chain kinase A from Dictyostelium possesses a novel actin-binding domain that cross-links actin filaments

2006 ◽  
Vol 395 (2) ◽  
pp. 373-383 ◽  
Author(s):  
Misty Russ ◽  
Daniel Croft ◽  
Omar Ali ◽  
Raquel Martinez ◽  
Paul A. Steimle
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Actin Filaments ◽  
Myosin Ii ◽  
Coiled Coil ◽  
Actin Binding ◽  
Coiled Coil Domain ◽  
Cross Links ◽  
Myosin Heavy Chain Kinase ◽  
Kinase A

Myosin heavy-chain kinase A (MHCK A) catalyses the disassembly of myosin II filaments in Dictyostelium cells via myosin II heavy-chain phosphorylation. MHCK A possesses a ‘coiled-coil’-enriched domain that mediates the oligomerization, cellular localization and actin-binding activities of the kinase. F-actin (filamentous actin) binding by the coiled-coil domain leads to a 40-fold increase in MHCK A activity. In the present study we examined the actin-binding characteristics of the coiled-coil domain as a means of identifying mechanisms by which MHCK A-mediated disassembly of myosin II filaments can be regulated in the cell. Co-sedimentation assays revealed that the coiled-coil domain of MHCK A binds co-operatively to F-actin with an apparent KD of approx. 0.5 μM and a stoichiometry of approx. 5:1 [actin/C(1–498)]. Further analyses indicate that the coiled-coil domain binds along the length of the actin filament and possesses at least two actin-binding regions. Quite surprisingly, we found that the coiled-coil domain cross-links actin filaments into bundles, indicating that MHCK A can affect the cytoskeleton in two important ways: (1) by driving myosin II-filament disassembly via myosin II heavy-chain phosphorylation, and (2) by cross-linking/bundling actin filaments. This discovery, along with other supporting data, suggests a model in which MHCK A-mediated bundling of actin filaments plays a central role in the recruitment and activation of the kinase at specific sites in the cell. Ultimately this provides a means for achieving the robust and highly localized disruption of myosin II filaments that facilitates polarized changes in cell shape during processes such as chemotaxis, cytokinesis and multicellular development.

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