scholarly journals MRIP Regulates the Myosin IIA Activity and DDR1 Function to Enable Collagen Tractional Remodeling

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1672
Author(s):  
Nuno M. Coelho ◽  
Andrew Wang ◽  
Petar Petrovic ◽  
Yongqiang Wang ◽  
Wilson Lee ◽  
...  
Keyword(s):  
Drug Target ◽  
Myosin Light Chain ◽  
Wound Closure ◽  
Myosin Phosphatase ◽  
Interacting Protein ◽  
Collagen Remodeling ◽  
Myosin Iia ◽  
Novel Drug ◽  
Muscle Myosin

DDR1 is a collagen adhesion-mechanoreceptor expressed in fibrotic lesions. DDR1 mediates non-muscle myosin IIA (NMIIA)-dependent collagen remodeling. We discovered that the myosin phosphatase Rho-interacting protein (MRIP), is enriched in DDR1-NMIIA adhesions on collagen. MRIP regulates RhoA- and myosin phosphatase-dependent myosin activity. We hypothesized that MRIP regulates DDR1-NMIIA interactions to enable cell migration and collagen tractional remodeling. After deletion of MRIP in β1-integrin null cells expressing DDR1, in vitro wound closure, collagen realignment, and contraction were reduced. Cells expressing DDR1 and MRIP formed larger and more abundant DDR1 clusters on collagen than cells cultured on fibronectin or cells expressing DDR1 but null for MRIP or cells expressing a non-activating DDR1 mutant. Deletion of MRIP reduced DDR1 autophosphorylation and blocked myosin light chain-dependent contraction. Deletion of MRIP did not disrupt the association of DDR1 with NMIIA. We conclude that MRIP regulates NMIIA-dependent DDR1 cluster growth and activation. Accordingly, MRIP may provide a novel drug target for dysfunctional DDR1-related collagen tractional remodeling in fibrosis.

scholarly journals 4E Interacting Protein as a Potential Novel Drug Target for Nucleoside Analogues in Trypanosoma Brucei

2021 ◽  
Vol 9 (4) ◽  
pp. 826
Author(s):  
Dorien Mabille ◽  
Camila Cardoso Santos ◽  
Rik Hendrickx ◽  
Mathieu Claes ◽  
Peter Takac ◽  
...  
Keyword(s):  
Mode Of Action ◽  
Drug Target ◽  
Drug Targets ◽  
De Novo ◽  
Treatment Options ◽  
Adenosine Kinase ◽  
Nucleoside Analogues ◽  
Purine Salvage ◽  
Interacting Protein ◽  
Novel Drug

Human African trypanosomiasis is a neglected parasitic disease for which the current treatment options are quite limited. Trypanosomes are not able to synthesize purines de novo and thus solely depend on purine salvage from the host environment. This characteristic makes players of the purine salvage pathway putative drug targets. The activity of known nucleoside analogues such as tubercidin and cordycepin led to the development of a series of C7-substituted nucleoside analogues. Here, we use RNA interference (RNAi) libraries to gain insight into the mode-of-action of these novel nucleoside analogues. Whole-genome RNAi screening revealed the involvement of adenosine kinase and 4E interacting protein into the mode-of-action of certain antitrypanosomal nucleoside analogues. Using RNAi lines and gene-deficient parasites, 4E interacting protein was found to be essential for parasite growth and infectivity in the vertebrate host. The essential nature of this gene product and involvement in the activity of certain nucleoside analogues indicates that it represents a potential novel drug target.

Ca2+-independent contraction of longitudinal ileal smooth muscle is potentiated by a zipper-interacting protein kinase pseudosubstrate peptide

2009 ◽  
Vol 297 (2) ◽  
pp. G361-G370 ◽  
Author(s):  
Eikichi Ihara ◽  
Lori Moffat ◽  
Meredith A. Borman ◽  
Jennifer E. Amon ◽  
Michael P. Walsh ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Conformational Changes ◽  
Kinase Inhibitor ◽  
Smooth Muscles ◽  
Dominant Negative ◽  
Myosin Phosphatase ◽  
Interacting Protein ◽  
Zipper Interacting Protein Kinase

As a regulator of smooth muscle contraction, zipper-interacting protein kinase (ZIPK) can directly phosphorylate the myosin regulatory light chains (LC20) and produce contractile force. Synthetic peptides (SM-1 and AV25) derived from the autoinhibitory region of smooth muscle myosin light chain kinase can inhibit ZIPK activity in vitro. Paradoxically, treatment of Triton-skinned ileal smooth muscle strips with AV25, but not SM-1, potentiated Ca2+-independent, microcystin- and ZIPK-induced contractions. The AV25-induced potentiation was limited to ileal and colonic smooth muscles and was not observed in rat caudal artery. Thus the potentiation of Ca2+-independent contractions by AV25 appeared to be mediated by a mechanism unique to intestinal smooth muscle. AV25 treatment elicited increased phosphorylation of LC20 (both Ser-19 and Thr-18) and myosin phosphatase-targeting subunit (MYPT1, inhibitory Thr-697 site), suggesting involvement of a Ca2+-independent LC20 kinase with coincident inhibition of myosin phosphatase. The phosphorylation of the inhibitor of myosin phosphatase, CPI-17, was not affected. The AV25-induced potentiation was abolished by pretreatment with staurosporine, a broad-specificity kinase inhibitor, but specific inhibitors of Rho-associated kinase, PKC, and MAPK pathways had no effect. When a dominant-negative ZIPK [kinase-dead ZIPK(1–320)-D161A] was added to skinned ileal smooth muscle, the potentiation of microcystin-induced contraction by AV25 was blocked. Furthermore, pretreatment of skinned ileal muscle with SM-1 abolished AV25-induced potentiation. We conclude, therefore, that, even though AV25 is an in vitro inhibitor of ZIPK, activation of the ZIPK pathway occurs following application of AV25 to permeabilized ileal smooth muscle. Finally, we propose a mechanism whereby conformational changes in the pseudosubstrate region of ZIPK permit augmentation of ZIPK activity toward LC20 and MYPT1 in situ. AV25 or molecules based on its structure could be used in therapeutic situations to induce contractility in diseases of the gastrointestinal tract associated with hypomotility.

scholarly journals Activation of the Sphingosine 1 Phosphate–Rho Pathway in Pterygium and in Ultraviolet-Irradiated Normal Conjunctiva

2019 ◽  
Vol 20 (19) ◽  
pp. 4670 ◽  
Author(s):  
Nozomi Igarashi ◽  
Megumi Honjo ◽  
Takashi Fujishiro ◽  
Tetsuya Toyono ◽  
Takashi Ono ◽  
...  
Keyword(s):  
Fibroblast Cell ◽  
Cellular Activity ◽  
Myosin Phosphatase ◽  
Potential Therapeutic Target ◽  
Interacting Protein ◽  
Cytoskeletal Organization ◽  
Rhoa Activity ◽  
Sphingosine 1 Phosphate ◽  
S1p Receptor

Sphingosine 1 phosphate (S1P) is a bioactive lipid that regulates cellular activity, including proliferation, cytoskeletal organization, migration, and fibrosis. In this study, the potential relevance of S1P–Rho signaling in pterygium formation and the effects of ultraviolet (UV) irradiation on activation of the S1P/S1P receptor axis and fibrotic responses were investigated in vitro. Expressions of the S1P2, S1P4, and S1P5 receptors were significantly higher in pterygium tissue than in normal conjunctiva, and the concentration of S1P was significantly elevated in the lysate of normal conjunctival fibroblast cell (NCFC) irradiated with UV (UV-NCFCs). RhoA activity was significantly upregulated in pterygium fibroblast cells (PFCs) and UV-NCFCs, and myosin phosphatase–Rho interacting protein (MRIP) was upregulated, and myosin phosphatase target subunit 1 (MYPT1) was downregulated in PFCs. Fibrogenic changes were significantly upregulated in both PFCs and UV-NCFCs compared to NCFCs. We found that the activation of the S1P receptor–Rho cascade was observed in pterygium tissue. Additionally, in vitro examination showed S1P–rho activation and fibrogenic changes in PFCs and UV-NCFCs. S1P elevation and the resulting upregulation of the downstream Rho signaling pathway may be important in pterygium formation; this pathway offers a potential therapeutic target for suppressing pterygium generation.

The E1841K Mutation in MYH-9 of a Patient with May-Hegglin Anomaly Inhibits the Disassembly of Non-Muscle Myosin IIA (MYH-9) Responsible for the Phenotype of the Disease.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 736-736 ◽  
Author(s):  
Koji Miyazaki ◽  
Satoshi Komatsu ◽  
Mariko Watanabe ◽  
Naoya Nakadate ◽  
Mitsuo Ikebe ◽  
...  
Keyword(s):  
Light Chain ◽  
Actin Filaments ◽  
Inclusion Bodies ◽  
Myosin Light Chain ◽  
Immunofluorescent Staining ◽  
Molecular Characteristics ◽  
Wild Type ◽  
Hel Cells ◽  
Myosin Iia ◽  
Muscle Myosin

Abstract It has been demonstrated that MYH-9 (non-muscle myosin IIA) is responsible for the hereditary macrothrombocytopenia, such as May-Hegglin Anomaly (MHA), Fechtner syndrome (FS) and Sebastian syndrome (SS). We identified the E1841K mutation of MYH-9 gene of a patient with May-Hegglin Anomaly. Immunofluorescent staining of her peripheral blood smear samples revealed that non-muscle myosin IIA and actin filaments were co-localized at the Döhle-like inclusion bodies of neutrophils. To investigate the mechanism by which the E1841K mutation causes the phenotype of MHA, we first expressed GFP-tagged wild type and E1841K mutant MYH-9 cDNA in NIH3T3 cells. The mutant was able to form filaments and some inclusion bodies such as Döhle-like bodies, although it seemed to make no influences on the shape of the fibroblasts. Next we expressed the GFP-tagged wild and E1841K mutant MYH-9 in HEL cells and induced differentiation with TPA. HEL cells expressing the E1841K mutant failed in full differentiation. They could not produce the proplatelet-like projections as the cells overexpressing wild type of MYH-9 did. These results demonstrate that overexpression of this mutant can induce some phenotype similar to MHA. To clarify what molecular characteristics of the mutant myosin can cause the MHA phenotype, we expressed the recombinant wild and mutant proteins of non-muscle myosin IIA using Baculo-virus system. The mutant myosin failed to dissolve even in high ionic strength, suggesting this mutant can assemble in cytoplasm even under the condition, in which wild type myosin changes the conformation and exchanges dynamically assembly to disassembly. Next we induced myosin filaments in HEL cells by over-expressing the mutant of myosin light chain (DD mutant), which mimics the double-phosphorylated form. The DD mutant of myosin light chain also inhibited the proplatelet-like projections. Moreover silencing of MYH-9 gene with siRNA could have no inhibitory effects on the differentiation of HEL cells, producing rather more proplatelet-like projections than the control. These results indicated that filament formation of myosin is not critical for proplatelet-like projections, but disassembly of myosin is rather essential. Collectively, the E1841K mutant inhibits the disassembly of myosin to prevent the proplatelet-like formation of HEL cells, and the assembled myosin forms the Döhle-like inclusion bodies probably with actin filaments.

Heterogeneous nuclear ribonucleoprotein A2B1, a novel drug target for hepatitis B virus infection

2021 ◽  
Author(s):  
Min Xu ◽  
Yu Chen ◽  
Hao-Yan Yuan ◽  
Yue-Hai Shen ◽  
Jia-Yao Xiang ◽  
...  
Keyword(s):  
Drug Target ◽  
Hbv Infection ◽  
Type I Interferons ◽  
Type I ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Deep Groove ◽  
Nuclear Ribonucleoprotein ◽  
Novel Drug

Abstract HBV infection is a major global health burden that needs novel immunotherapeutic approaches. Herein, we show that heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) is a novel drug target for HBV infection. We reveal the new target with highly selective probes of PAC5, a natural sesquiterpene derivative. PAC5 show potent anti-HBV activity in vivo and in vitro. Further studies on its mode of action indicate that PAC5 binds to the residue Asp49 and a deep groove in the RNA recognition motif1 (RRM1) region of hnRNPA2B1. PAC5-bound hnRNPA2B1 is activated, dimerized, and translocated to the cytoplasm where it activates the TBK1-IRF3 pathway, leading to the production of type I interferons (IFNs). Furthermore, PAC5 also suppresses other viral replications, such as SARS-CoV-2 and vesicular stomatitis virus (VSV). Our results indicate that PAC5 is the first small molecule agonist of hnRNPA2B1, a drug target potentially valid for broad-spectrum viral infections, providing a novel strategy for viral immunotherapy.

scholarly journals Dephosphorylation of distinct sites on the 20 kDa myosin light chain by smooth muscle myosin phosphatase

FEBS Letters ◽  
1999 ◽  
Vol 448 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Jianhua Feng ◽  
Masaaki Ito ◽  
Masakatsu Nishikawa ◽  
Tsutomu Okinaka ◽  
Naoki Isaka ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Smooth Muscle Myosin ◽  
Myosin Phosphatase ◽  
Muscle Myosin
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