scholarly journals Microtubule Asymmetry during Neutrophil Polarization and Migration

2002 ◽  
Vol 13 (12) ◽  
pp. 4470-4483 ◽  
Author(s):  
Robert J. Eddy ◽  
Lynda M. Pierini ◽  
Frederick R. Maxfield
Keyword(s):  
Cell Polarity ◽  
Myosin Light Chain Kinase ◽  
Large Scale ◽  
Myosin Light Chain ◽  
Kinase Inhibitor ◽  
Myosin Ii ◽  
Cytochalasin D ◽  
Polymorphonuclear Neutrophils ◽  
Specific Marker ◽  
And Migration

The development of cell polarity in response to chemoattractant stimulation in human polymorphonuclear neutrophils (PMNs) is characterized by the rapid conversion from round to polarized morphology with a leading lamellipod at the front and a uropod at the rear. During PMN polarization, the microtubule (MT) array undergoes a dramatic reorientation toward the uropod that is maintained during motility and does not require large-scale MT disassembly or cell adhesion to the substratum. MTs are excluded from the leading lamella during polarization and motility, but treatment with a myosin light chain kinase inhibitor (ML-7) or the actin-disrupting drug cytochalasin D causes an expansion of the MT array and penetration of MTs into the lamellipod. Depolymerization of the MT array before stimulation caused 10% of the cells to lose their polarity by extending two opposing lateral lamellipodia. These multipolar cells showed altered localization of a leading lamella-specific marker, talin, and a uropod-specific marker, CD44. In summary, these results indicate that F-actin– and myosin II-dependent forces lead to the development and maintenance of MT asymmetry that may act to reinforce cell polarity during PMN migration.

scholarly journals A Novel Regulatory Mechanism of Myosin Light Chain Phosphorylation via Binding of 14-3-3 to Myosin Phosphatase

2008 ◽  
Vol 19 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Yasuhiko Koga ◽  
Mitsuo Ikebe
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Regulatory Mechanism ◽  
Kinase Inhibitor ◽  
Myosin Ii ◽  
Critical Role ◽  
Rho Kinase ◽  
Myosin Phosphatase ◽  
Dependent Cell ◽  
Direct Binding

Myosin II phosphorylation–dependent cell motile events are regulated by myosin light-chain (MLC) kinase and MLC phosphatase (MLCP). Recent studies have revealed myosin phosphatase targeting subunit (MYPT1), a myosin-binding subunit of MLCP, plays a critical role in MLCP regulation. Here we report the new regulatory mechanism of MLCP via the interaction between 14-3-3 and MYPT1. The binding of 14-3-3β to MYPT1 diminished the direct binding between MYPT1 and myosin II, and 14-3-3β overexpression abolished MYPT1 localization at stress fiber. Furthermore, 14-3-3β inhibited MLCP holoenzyme activity via the interaction with MYPT1. Consistently, 14-3-3β overexpression increased myosin II phosphorylation in cells. We found that MYPT1 phosphorylation at Ser472 was critical for the binding to 14-3-3. Epidermal growth factor (EGF) stimulation increased both Ser472 phosphorylation and the binding of MYPT1-14-3-3. Rho-kinase inhibitor inhibited the EGF-induced Ser472 phosphorylation and the binding of MYPT1-14-3-3. Rho-kinase specific siRNA also decreased EGF-induced Ser472 phosphorylation correlated with the decrease in MLC phosphorylation. The present study revealed a new RhoA/Rho-kinase–dependent regulatory mechanism of myosin II phosphorylation by 14-3-3 that dissociates MLCP from myosin II and attenuates MLCP activity.

scholarly journals Myosin light chain kinase-regulated endothelial cell contraction: the relationship between isometric tension, actin polymerization, and myosin phosphorylation.

1995 ◽  
Vol 130 (3) ◽  
pp. 613-627 ◽  
Author(s):  
Z M Goeckeler ◽  
R B Wysolmerski
Keyword(s):  
Endothelial Cell ◽  
Light Chain ◽  
Isometric Contraction ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Isometric Tension ◽  
Stress Fibers ◽  
Light Chains ◽  
Myosin Light Chains

The phosphorylation of regulatory myosin light chains by the Ca2+/calmodulin-dependent enzyme myosin light chain kinase (MLCK) has been shown to be essential and sufficient for initiation of endothelial cell retraction in saponin permeabilized monolayers (Wysolmerski, R. B. and D. Lagunoff. 1990. Proc. Natl. Acad. Sci. USA. 87:16-20). We now report the effects of thrombin stimulation on human umbilical vein endothelial cell (HUVE) actin, myosin II and the functional correlate of the activated actomyosin based contractile system, isometric tension development. Using a newly designed isometric tension apparatus, we recorded quantitative changes in isometric tension from paired monolayers. Thrombin stimulation results in a rapid sustained isometric contraction that increases 2- to 2.5-fold within 5 min and remains elevated for at least 60 min. The phosphorylatable myosin light chains from HUVE were found to exist as two isoforms, differing in their molecular weights and isoelectric points. Resting isometric tension is associated with a basal phosphorylation of 0.54 mol PO4/mol myosin light chain. After thrombin treatment, phosphorylation rapidly increases to 1.61 mol PO4/mol myosin light chain within 60 s and remains elevated for the duration of the experiment. Myosin light chain phosphorylation precedes the development of isometric tension and maximal phosphorylation is maintained during the sustained phase of isometric contraction. Tryptic phosphopeptide maps from both control and thrombin-stimulated cultures resolve both monophosphorylated Ser-19 and diphosphorylated Ser-19/Thr-18 peptides indicative of MLCK activation. Changes in the polymerization of actin and association of myosin II correlate temporally with the phosphorylation of myosin II and development of isometric tension. Activation results in a 57% increase in F-actin content within 90 s and 90% of the soluble myosin II associates with the reorganizing F-actin. Furthermore, the disposition of actin and myosin II undergoes striking reorganization. F-actin initially forms a fine network of filaments that fills the cytoplasm and then reorganizes into prominent stress fibers. Myosin II rapidly forms discrete aggregates associated with the actin network and by 2.5 min assumes a distinct periodic distribution along the stress fibers.

scholarly journals Zinc exocytosis is sensitive to myosin light chain kinase inhibition in mouse and human eggs

2020 ◽  
Vol 26 (4) ◽  
pp. 228-239 ◽  
Author(s):  
Hoi Chang Lee ◽  
Maxwell E Edmonds ◽  
Francesca E Duncan ◽  
Thomas V O’Halloran ◽  
Teresa K Woodruff
Keyword(s):  
Embryo Development ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Kinase Inhibitor ◽  
Early Embryo ◽  
Egg Activation ◽  
Cortical Granules ◽  
Preimplantation Embryo Development ◽  
Egg Maturation

Abstract Zinc dynamics are essential for oocyte meiotic maturation, egg activation, and preimplantation embryo development. During fertilisation and egg activation, the egg releases billions of zinc atoms (Zn2+) in an exocytotic event termed the ‘zinc spark’. We hypothesised that this zinc transport and exocytosis is dependent upon the intracellular trafficking of cortical granules (CG) which requires myosin-actin-dependent motors. Treatment of mature mouse and human eggs with ML-7, a myosin light chain kinase inhibitor (MLCK), resulted in an 80% reduction in zinc spark intensity compared to untreated controls when activated with ionomycin. Moreover, CG migration towards the plasma membrane was significantly decreased in ML-7-treated eggs compared with controls when activated parthenogenetically with ionomycin. In sperm-induced fertilisation via intracytoplasmic sperm injection (ICSI), ML-7-treated mouse eggs exhibited decreased labile zinc intensity and cortical CG staining. Collectively, these data demonstrate that ML-7 treatment impairs zinc release from both murine and human eggs after activation, demonstrating that zinc exocytosis requires myosin light chain kinase activity. Further, these results provide additional support that zinc is likely stored and released from CGs. These data underscore the importance of intracellular zinc trafficking as a crucial component of egg maturation necessary for egg activation and early embryo development.

scholarly journals Myosin light chain kinase regulates cell polarization independently of membrane tension or Rho kinase

2015 ◽  
Vol 209 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Sunny S. Lou ◽  
Alba Diz-Muñoz ◽  
Orion D. Weiner ◽  
Daniel A. Fletcher ◽  
Julie A. Theriot
Keyword(s):  
Cell Polarity ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Rho Kinase ◽  
Model System ◽  
Cell Polarization ◽  
Membrane Tension ◽  
Specific Mechanism

Cells polarize to a single front and rear to achieve rapid actin-based motility, but the mechanisms preventing the formation of multiple fronts are unclear. We developed embryonic zebrafish keratocytes as a model system for investigating establishment of a single axis. We observed that, although keratocytes from 2 d postfertilization (dpf) embryos resembled canonical fan-shaped keratocytes, keratocytes from 4 dpf embryos often formed multiple protrusions despite unchanged membrane tension. Using genomic, genetic, and pharmacological approaches, we determined that the multiple-protrusion phenotype was primarily due to increased myosin light chain kinase (MLCK) expression. MLCK activity influences cell polarity by increasing myosin accumulation in lamellipodia, which locally decreases protrusion lifetime, limiting lamellipodial size and allowing for multiple protrusions to coexist within the context of membrane tension limiting protrusion globally. In contrast, Rho kinase (ROCK) regulates myosin accumulation at the cell rear and does not determine protrusion size. These results suggest a novel MLCK-specific mechanism for controlling cell polarity via regulation of myosin activity in protrusions.

Myosin Light Chain Kinase Inhibitor Inhibits Dextran Sulfate Sodium-Induced Colitis in Mice

2012 ◽  
Vol 58 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Xiaochang Liu ◽  
Jianming Xu ◽  
Qiao Mei ◽  
Liang Han ◽  
Jian Huang
Keyword(s):  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Dextran Sulfate ◽  
Dextran Sulfate Sodium ◽  
Kinase Inhibitor

Myosin light chain kinase inhibitor attenuates atherosclerosis and permeability via reduced endothelial tight junction in rabbits

2013 ◽  
Vol 168 (5) ◽  
pp. 5042-5043 ◽  
Author(s):  
Hua-Qing Zhu ◽  
Xiao-Bian Wang ◽  
Jian-Xiong Han ◽  
Ze-Ping Hu ◽  
Yi Wang ◽  
...  
Keyword(s):  
Tight Junction ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Kinase Inhibitor ◽  
Endothelial Tight Junction

scholarly journals Total Synthesis of MS-444, a Myosin Light Chain Kinase Inhibitor

1997 ◽  
Vol 50 (3) ◽  
pp. 289-290 ◽  
Author(s):  
KUNIAKI TATSUTA ◽  
TAKUJI YOSHIMOTO ◽  
HIROKI GUNJI
Keyword(s):  
Total Synthesis ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Kinase Inhibitor

scholarly journals Participation of protein kinases in complement C5b-9-induced shedding of platelet plasma membrane vesicles

Blood ◽  
1991 ◽  
Vol 78 (11) ◽  
pp. 2880-2886
Author(s):  
T Wiedmer ◽  
PJ Sims
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Kinase Inhibitor ◽  
Complement Proteins ◽  
Cellular Events ◽  
Microparticle Formation ◽  
Terminal Complement

The formation of membrane microparticles through vesiculation of the platelet plasma membrane is known to provide catalytic surface for several enzyme complexes of the coagulation system, and to underlie the procoagulant responses elicited with platelet activation. This induced shedding of vesicles from the plasma membrane is most prominent when platelets are activated by the terminal complement proteins, C5b-9, by a Ca2+ ionophore, or by the combination of thrombin plus collagen. Although shown to require elevated [Ca2+], the cellular events that initiate plasma membrane evagination and fusion to form the shed vesicles remain unresolved. To gain additional insight into the cellular events that regulate membrane microparticle formation, we have examined how this process is influenced by the activity of cellular protein kinases. Cytoplasmic [Ca2+] of gel-filtered platelets was increased by membrane assembly of the terminal complement proteins C5b- 9 in the presence of selective inhibitors of protein kinase or phosphatase reactions, and resulting microparticle formation was quantitated by fluorescence-gated flow cytometry. Pre-equilibration of the phosphatase inhibitor vanadate into the platelet cytosol increased microparticle formation by as much as 40%, suggesting that vesiculation of the platelet plasma membrane is influenced by the state of phosphorylation of a cellular constituent. By contrast to the stimulatory effects of vanadate, microparticle formation was partially inhibited in platelets treated with the protein kinase inhibitor sphingosine, the myosin light chain kinase inhibitor ML-7, the calmodulin-antagonist W-7, and under conditions of elevated cytosolic concentration of cyclic adenosine monophosphate. These results indicate that complement-induced platelet microparticle formation is influenced by one or more protein kinase(s) as well as by calmodulin, and suggest a role for the platelet myosin light chain kinase or another Ca(2+)- pluscalmodulin-regulated membrane component.

Sign in / Sign up

Export Citation Format

Share Document