Inhibition of agonist-stimulated inositol 1,4,5-trisphosphate production and calcium signaling by the myosin light chain kinase inhibitor, wortmannin.

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.

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Myosin light chain kinase inhibitor ML7 improves vascular endothelial dysfunction via tight junction regulation in a rabbit model of atherosclerosis

Molecular Medicine Reports ◽

10.3892/mmr.2015.3973 ◽

2015 ◽

Vol 12 (3) ◽

pp. 4109-4116 ◽

Cited By ~ 15

Author(s):

XIAOWEN CHENG ◽

XIAOBIAN WANG ◽

YUFENG WAN ◽

QING ZHOU ◽

HUAQING ZHU ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Tight Junction ◽

Light Chain ◽

Myosin Light Chain Kinase ◽

Myosin Light Chain ◽

Kinase Inhibitor ◽

Rabbit Model ◽

Vascular Endothelial ◽

Vascular Endothelial Dysfunction ◽

Tight Junction Regulation

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

Digestive Diseases and Sciences ◽

10.1007/s10620-012-2304-3 ◽

2012 ◽

Vol 58 (1) ◽

pp. 107-114 ◽

Cited By ~ 16

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

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

International Journal of Cardiology ◽

10.1016/j.ijcard.2013.07.219 ◽

2013 ◽

Vol 168 (5) ◽

pp. 5042-5043 ◽

Cited By ~ 7

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

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

The Journal of Antibiotics ◽

10.7164/antibiotics.50.289 ◽

1997 ◽

Vol 50 (3) ◽

pp. 289-290 ◽

Cited By ~ 12

Author(s):

KUNIAKI TATSUTA ◽

TAKUJI YOSHIMOTO ◽

HIROKI GUNJI

Keyword(s):

Total Synthesis ◽

Light Chain ◽

Myosin Light Chain Kinase ◽

Myosin Light Chain ◽

Kinase Inhibitor

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

Blood ◽

10.1182/blood.v78.11.2880.bloodjournal78112880 ◽

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.

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A calmodulin antagonist reveals a calmodulin-independent interdomain interaction essential for activation of inositol 1,4,5-trisphosphate receptors

Biochemical Journal ◽

10.1042/bj20080861 ◽

2008 ◽

Vol 416 (2) ◽

pp. 243-253 ◽

Cited By ~ 12

Author(s):

Yi Sun ◽

Colin W. Taylor

Keyword(s):

Light Chain ◽

Myosin Light Chain Kinase ◽

Myosin Light Chain ◽

Channel Gating ◽

Binding Motif ◽

Calmodulin Antagonist ◽

Binding Peptide ◽

Selective Antagonist ◽

Inositol 1,4,5 Trisphosphate ◽

Interdomain Interaction

CaM (calmodulin) has been implicated in the regulation of IP3R [IP3 (inositol 1,4,5-trisphosphate) receptors] and a recent report suggested that CaM tightly tethered to IP3R was essential for IP3R activation [Nadif Kasri, Torok, Galione, Garnham, Callewaert, Missiaen, Parys and De Smedt (2006) J. Biol. Chem. 281, 8332–8338]. In the present study, we confirm that a CaM-binding peptide derived from MLCK (myosin light chain kinase) inhibits IP3-evoked Ca2+ release via all three IP3R subtypes. However, inhibition by MLCK peptide is not mimicked by other CaM antagonists that effectively block regulation of IP3R by CaM. Inhibition by MLCK peptide is rapid, fully reversible and occurs under conditions where there is no CaM associated with IP3R. MLCK peptide stimulates IP3 binding to IP3R1 and to its bacterially expressed N-terminal, but not after removal of the suppressor domain (residues 1–224). We suggest that MLCK peptide mimics a sequence within the suppressor domain that is similar to a 1-8-14 CaM-binding motif. The peptide may thereby unzip an interdomain interaction that is essential for IP3R activation. We conclude that CaM is not essential for IP3R activation, and that MLCK peptide is a selective antagonist of the IP3R that binds directly to the N-terminal to uncouple IP3 binding from channel gating. The results of the present study highlight the importance of the suppressor domain in IP3R activation and suggest that MLCK peptide may provide a route to novel non-competitive antagonists of IP3R.

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