scholarly journals Cofilin is an essential component of the yeast cortical cytoskeleton.

1993 ◽  
Vol 120 (2) ◽  
pp. 421-435 ◽  
Author(s):  
A L Moon ◽  
P A Janmey ◽  
K A Louie ◽  
D G Drubin
Keyword(s):  
Sequence Similarity ◽  
Actin Binding ◽  
Actin Assembly ◽  
The Family ◽  
Multiple Copies ◽  
Complete Disruption ◽  
Diploid Cells ◽  
Related Proteins

We have biochemically identified the Saccharomyces cerevisiae homologue of the mammalian actin binding protein cofilin. Cofilin and related proteins isolated from diverse organisms are low molecular weight proteins (15-20 kD) that possess several activities in vitro. All bind to monomeric actin and sever filaments, and some can stably associate with filaments. In this study, we demonstrate using viscosity, sedimentation, and actin assembly rate assays that yeast cofilin (16 kD) possesses all of these properties. Cloning and sequencing of the S. cerevisiae cofilin gene (COF1) revealed that yeast cofilin is 41% identical in amino acid sequence to mammalian cofilin and, surprisingly, has homology to a protein outside the family of cofilin-like proteins. The NH2-terminal 16kD of Abp1p, a 65-kD yeast protein identified by its ability to bind to actin filaments, is 23% identical to yeast cofilin. Immunofluorescence experiments showed that, like Abp1p, cofilin is associated with the membrane actin cytoskeleton. A complete disruption of the COF1 gene was created in diploid cells. Sporulation and tetrad analysis revealed that yeast cofilin has an essential function in vivo. Although Abp1p shares sequence similarity with cofilin and has the same distribution as cofilin in the cell, multiple copies of the ABP1 gene cannot compensate for the loss of cofilin. Thus, cofilin and Abp1p are structurally related but functionally distinct components of the yeast membrane cytoskeleton.

scholarly journals Isolation and characterization of a regulated form of actin depolymerizing factor

1993 ◽  
Vol 122 (3) ◽  
pp. 623-633 ◽  
Author(s):  
TE Morgan ◽  
RO Lockerbie ◽  
LS Minamide ◽  
MD Browning ◽  
JR Bamburg
Keyword(s):  
Muscle Development ◽  
Peptide Mapping ◽  
Actin Binding ◽  
Actin Assembly ◽  
Actin Depolymerizing Factor ◽  
Isolation And Characterization ◽  
Relative Molecular Weight

Actin depolymerizing factor (ADF) is an 18.5-kD protein with pH-dependent reciprocal F-actin binding and severing/depolymerizing activities. We previously showed developing muscle down-regulates ADF (J. R. Bamburg and D. Bray. 1987. J. Cell Biol. 105: 2817-2825). To further study this process, we examined ADF expression in chick myocytes cultured in vitro. Surprisingly, ADF immunoreactivity increases during the first 7-10 d in culture. This increase is due to the presence of a new ADF species with higher relative molecular weight which reacts identically to brain ADF with antisera raised against either brain ADF or recombinant ADF. We have purified both ADF isoforms from myocytes and have shown by peptide mapping and partial sequence analysis that the new isoform is structurally related to ADF. Immunoprecipitation of both isoforms from extracts of cells prelabeled with [32P]orthophosphate showed that the new isoform is radiolabeled, predominantly on a serine residue, and hence is called pADF. pADF can be converted into a form which comigrates with ADF on 1-D and 2-D gels by treatment with alkaline phosphatase. pADF has been quantified in a number of cells and tissues where it is present from approximately 18% to 150% of the amount of unphosphorylated ADF. pADF, unlike ADF, does not bind to G-actin, or affect the rate or extent of actin assembly. Four ubiquitous protein kinases failed to phosphorylate ADF in vitro suggesting that ADF phosphorylation in vivo is catalyzed by a more specific kinase. We conclude that the ability to regulate ADF activity is important to muscle development since myocytes have both pre- and posttranslational mechanisms for regulating ADF activity. The latter mechanism is apparently a general one for cell regulation of ADF activity.

scholarly journals CORO1C is Associated With Poor Prognosis and Promotes Metastasis Through PI3K/AKT Pathway in Colorectal Cancer

2021 ◽  
Vol 8 ◽  
Author(s):  
Zongxia Wang ◽  
Lizhou Jia ◽  
Yushu sun ◽  
Chunli Li ◽  
Lingli Zhang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Signaling Pathway ◽  
Poor Prognosis ◽  
Akt Signaling ◽  
Actin Binding ◽  
Migration And Invasion ◽  
Akt Signaling Pathway ◽  
Related Proteins

Trophoblast cell surface protein 2 (Trop2) is one of the cancer-related proteins that plays a vital role in biological aggressiveness and poor prognosis of colorectal cancer (CRC). The study of the Trop2 related network is helpful for us to understand the mechanism of tumorigenesis. However, the effects of the related proteins interacting with Trop2 in CRC remain unclear. Here, we found that coronin-like actin-binding protein 1C (CORO1C) could interact with Trop2 and the expression of CORO1C in CRC tissues was higher than that in paracarcinoma tissues. The expression of CORO1C was associated with histological type, lymph node metastasis, distant metastasis, AJCC stage, venous invasion, and perineural invasion. The correlation between CORO1C expression and clinical characteristics was analyzed demonstrating that high CORO1C expression in CRC patients were associated with poor prognosis. Furthermore, CORO1C knockdown could decrease the cell proliferation, colony formation, migration and invasion in vitro and tumor growth in vivo. The underlying mechanisms were predicted by bioinformatics analysis and verified by Western blotting. We found that PI3K/AKT signaling pathway was significantly inhibited by CORO1C knockdown and the tuomr-promoting role of CORO1C was leastwise partly mediated by PI3K/AKT signaling pathway. Thus, CORO1C may be a valuable prognostic biomarker and drug target in CRC patients.

scholarly journals Distinct phospho-forms of cortactin differentially regulate actin polymerization and focal adhesions

2008 ◽  
Vol 295 (5) ◽  
pp. C1113-C1122 ◽  
Author(s):  
Anne E. Kruchten ◽  
Eugene W. Krueger ◽  
Yu Wang ◽  
Mark A. McNiven
Keyword(s):  
Cell Migration ◽  
Focal Adhesion ◽  
Actin Polymerization ◽  
Control Cell ◽  
Focal Adhesions ◽  
Serine Phosphorylation ◽  
Actin Binding ◽  
Actin Assembly

Cortactin is an actin-binding protein that is overexpressed in many cancers and is a substrate for both tyrosine and serine/threonine kinases. Tyrosine phosphorylation of cortactin has been observed to increase cell motility and invasion in vivo, although it has been reported to have both positive and negative effects on actin polymerization in vitro. In contrast, serine phosphorylation of cortactin has been shown to stimulate actin assembly in vitro. Currently, the effects of cortactin serine phosphorylation on cell migration are unclear, and furthermore, how the distinct phospho-forms of cortactin may differentially contribute to cell migration has not been directly compared. Therefore, we tested the effects of different tyrosine and serine phospho-mutants of cortactin on lamellipodial protrusion, actin assembly within cells, and focal adhesion dynamics. Interestingly, while expression of either tyrosine or serine phospho-mimetic cortactin mutants resulted in increased lamellipodial protrusion and cell migration, these effects appeared to be via distinct processes. Cortactin mutants mimicking serine phosphorylation appeared to predominantly affect actin polymerization, whereas mutation of cortactin tyrosine residues resulted in alterations in focal adhesion turnover. Thus these findings provide novel insights into how distinct phospho-forms of cortactin may differentially contribute to actin and focal adhesion dynamics to control cell migration.

scholarly journals Actin activatesPseudomonas aeruginosaExoY nucleotidyl cyclase toxin and ExoY-like effector domains from MARTX toxins

2015 ◽  
Author(s):  
Dorothee Raoux-Barbot ◽  
Cosmin Saveanu ◽  
Abdelkader Namane ◽  
Vasily Ogryzko ◽  
Lina Worpenberg ◽  
...  
Keyword(s):  
Actin Binding ◽  
Target Cells ◽  
Actin Assembly ◽  
Filamentous Actin ◽  
Severe Damage ◽  
Chronic Infections ◽  
Effector Domains ◽  
Host Target

Pseudomonas aeruginosa is a major cause of chronic infections in cystic fibrosis patients. The nucleotidyl cyclase toxin ExoY is a virulence factors injected by the pathogen and associated with severe damage to lung tissue. ExoY-like cyclases are also found in other Gram-negative pathogens and shown to contribute to virulence, although they remained poorly characterized. Here we demonstrate that filamentous actin (F-actin) is the hitherto unknown co-factor that activates P. aeruginosa ExoY within host target cells. Highly purified actin, when polymerized into filaments, potently stimulates (>10,000 fold) ExoY activity. ExoY co-localizes in vivo with actin filaments in transfected cells and, in vitro, it interferes with the regulation of actin assembly/disassembly-dynamics mediated by important F-actin-binding proteins. We further show that actin also activates an ExoY-like adenylate cyclase from a Vibrio species. Our results thus highlight a new sub-class within the class II adenylyl cyclase family, defined as actin-activated nucleotidyl cyclase (AA-NC) toxins.

scholarly journals Specific Interaction of the Actin-binding Domain of Dystrophin with Intermediate Filaments Containing Keratin 19

2005 ◽  
Vol 16 (9) ◽  
pp. 4280-4293 ◽  
Author(s):  
Michele R. Stone ◽  
Andrea O'Neill ◽  
Dawn Catino ◽  
Robert J. Bloch
Keyword(s):  
Striated Muscle ◽  
Specific Interaction ◽  
Binding Domain ◽  
Actin Binding ◽  
Glycoprotein Complex ◽  
Actin Binding Domain ◽  
Dystrophin Glycoprotein Complex ◽  
Related Proteins

Cytokeratins 8 and 19 concentrate at costameres of striated muscle and copurify with the dystrophin-glycoprotein complex, perhaps through the interaction of the cytokeratins with the actin-binding domain of dystrophin. We overexpressed dystrophin's actin-binding domain (Dys-ABD), K8 and K19, as well as closely related proteins, in COS-7 cells to assess the basis and specificity of their interaction. Dys-ABD alone associated with actin microfilaments. Expressed with K8 and K19, which form filaments, Dys-ABD associated preferentially with the cytokeratins. This interaction was specific, as the homologous ABD of βI-spectrin failed to interact with K8/K19 filaments, and Dys-ABD did not associate with desmin or K8/K18 filaments. Studies in COS-7 cells and in vitro showed that Dys-ABD binds directly and specifically to K19. Expressed in muscle fibers in vivo, K19 accumulated in the myoplasm in structures that contained dystrophin and spectrin and disrupted the organization of the sarcolemma. K8 incorporated into sarcomeres, with no effect on the sarcolemma. Our results show that dystrophin interacts through its ABD with K19 specifically and are consistent with the idea that cytokeratins associate with dystrophin at the sarcolemma of striated muscle.

A Comparison of the Effect of Decorsin and Two Disintegrins, Albolabrin and Eristostatin, on Platelet Function

1995 ◽  
Vol 74 (05) ◽  
pp. 1316-1322 ◽  
Author(s):  
Mary Ann McLane ◽  
Jagadeesh Gabbeta ◽  
A Koneti Rao ◽  
Lucia Beviglia ◽  
Robert A Lazarus ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Sequence Similarity ◽  
Platelet Aggregation Inhibitors ◽  
Antiplatelet Drug ◽  
Rgd Sequence ◽  
Fibrinogen Receptor ◽  
Activated Platelets

SummaryNaturally-occurring fibrinogen receptor antagonists and platelet aggregation inhibitors that are found in snake venom (disintegrins) and leeches share many common features, including an RGD sequence, high cysteine content, and low molecular weight. There are, however, significant selectivity and potency differences. We compared the effect of three proteins on platelet function: albolabrin, a 7.5 kDa disintegrin, eristostatin, a 5.4 kDa disintegrin in which part of the disintegrin domain is deleted, and decorsin, a 4.5 kDa non-disintegrin derived from the leech Macrobdella decora, which has very little sequence similarity with either disintegrin. Decorsin was about two times less potent than albolabrin and six times less potent than eristostatin in inhibiting ADP- induced human platelet aggregation. It had a different pattern of interaction with glycoprotein IIb/IIIa as compared to the two disintegrins. Decorsin bound with a low affinity to resting platelets (409 nM) and to ADP-activated platelets (270 nM), and with high affinity to thrombin- activated platelets (74 nM). At concentrations up to 685 nM, it did not cause expression of a ligand-induced binding site epitope on the (β3 subunit of the GPIIb/IIIa complex. It did not significantly inhibit isolated GPIIb/IIIa binding to immobilized von Willebrand Factor. At low doses (1.5-3.0 μg/mouse), decorsin protected mice against death from pulmonary thromboembolism, showing an effect similar to eristostatin. This suggested that decorsin is a much more potent inhibitor of platelet aggregation in vivo than in vitro, and it may have potential as an antiplatelet drug.

The Development of Homologous (Canine/Anti-Canine) Antibodies in Dogs with Haemophilia A (Factor VIII Deficiency): A Ten-Year Longitudinal Study

1993 ◽  
Vol 69 (01) ◽  
pp. 021-024 ◽  
Author(s):  
Shawn Tinlin ◽  
Sandra Webster ◽  
Alan R Giles
Keyword(s):  
Factor Viii ◽  
Canine Model ◽  
Significant Inhibition ◽  
Human Condition ◽  
Haemophilia A ◽  
Variable Expression ◽  
The Family ◽  
Over Time

SummaryThe development of inhibitors to factor VIII in patients with haemophilia A remains as a serious complication of replacement therapy. An apparently analogous condition has been described in a canine model of haemophilia A (Giles et al., Blood 1984; 63:451). These animals and their relatives have now been followed for 10 years. The observation that the propensity for inhibitor development was not related to the ancestral factor VIII gene has been confirmed by the demonstration of vertical transmission through three generations of the segment of the family related to a normal (non-carrier) female that was introduced for breeding purposes. Haemophilic animals unrelated to this animal have not developed functionally significant factor VIII inhibitors despite intensive factor VIII replacement. Two animals have shown occasional laboratory evidence of factor VIII inhibition but this has not been translated into clinical significant inhibition in vivo as assessed by clinical response and F.VIII recovery and survival characteristics. Substantial heterogeneity of inhibitor expression both in vitro and in vivo has been observed between animals and in individual animals over time. Spontaneous loss of inhibitors has been observed without any therapies designed to induce tolerance, etc., being instituted. There is also phenotypic evidence of polyclonality of the immune response with variable expression over time in a given animal. These observations may have relevance to the human condition both in determining the pathogenetic factors involved in this condition and in highlighting the heterogeneity of its expression which suggests the need for caution in the interpretation of the outcome of interventions designed to modulate inhibitor activity.

scholarly journals Dipterocarpus tuberculatus Roxb. Ethanol Extract Has Anti-Inflammatory and Hepatoprotective Effects In Vitro and In Vivo by Targeting the IRAK1/AP-1 Pathway

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2529
Author(s):  
Haeyeop Kim ◽  
Woo Seok Yang ◽  
Khin Myo Htwe ◽  
Mi-Nam Lee ◽  
Young-Dong Kim ◽  
...  
Keyword(s):  
Ethanol Extract ◽  
Serum Levels ◽  
Hepatoprotective Activity ◽  
Tnf Α ◽  
Anti Inflammatory ◽  
Related Proteins ◽  
Pro Inflammatory Cytokines ◽  
Inflammatory Effect

Dipterocarpus tuberculatus Roxb. has been used traditionally as a remedy for many diseases, especially inflammation. Therefore, we analyzed and explored the mechanism of the anti-inflammatory effect of a Dipterocarpus tuberculatus Roxb. ethanol extract (Dt-EE). Dt-EE clearly and dose-dependently inhibited the expression of pro-inflammatory cytokines such as IL-6, TNF-α, and IL-1β in lipopolysaccharide (LPS)-treated RAW264.7 cells. Also, Dt-EE suppressed the activation of the MyD88/TRIF-mediated AP-1 pathway and the AP-1 pathway related proteins JNK2, MKK4/7, and TAK1, which occurred as a result of inhibiting the kinase activity of IRAK1 and IRAK4, the most upstream factors of the AP-1 pathway. Finally, Dt-EE displayed hepatoprotective activity in a mouse model of hepatitis induced with LPS/D-galactosamine (D-GalN) through decreasing the serum levels of alanine aminotransferase and suppressing the activation of JNK and IRAK1. Therefore, our results strongly suggest that Dt-EE could be a candidate anti-inflammatory herbal medicine with IRAK1/AP-1 inhibitory and hepatoprotective properties.

scholarly journals miR-146a-5p Promotes Chondrocyte Apoptosis and Inhibits Autophagy of Osteoarthritis by Targeting NUMB

Cartilage ◽  
2021 ◽  
pp. 194760352110235
Author(s):  
Hongjun Zhang ◽  
Wendi Zheng ◽  
Du Li ◽  
Jia Zheng
Keyword(s):  
Caspase 3 ◽  
Cartilage Tissue ◽  
Luciferase Reporter ◽  
Chondrocyte Apoptosis ◽  
Knee Cartilage ◽  
Before And After ◽  
Related Proteins ◽  
Human And Mouse

Objective miR-146a-5p was found to be significantly upregulated in cartilage tissue of patients with osteoarthritis (OA). NUMB was shown to be involved in the autophagy regulation process of cells. We aimed to learn whether NUMB was involved in the apoptosis or autophagy process of chondrocytes in OA and related with miR-146a-5p. Methods QRT-PCR was used to detect miR-146a-5p level in 22 OA cartilage tissues and 22 controls. The targets of miR-146a-5p were analyzed using software and the luciferase reporter experiment. The apoptosis and autophagy, and related proteins were detected in chondrocytes treated with miR-146a-5p mimic/inhibitor or pcDNA3.1-NUMB/si-NUMB and IL-1β, respectively. In vivo experiment, intra-articular injection of miR-146a-5p antagomir/NC was administered at the knee of OA male mice before and after model construction. Chondrocyte apoptosis and the expression of apoptosis and autophagy-related proteins were also detected. Results miR-146a-5p was highly expressed in knee cartilage tissue of patients with OA, while NUMB was lowly expressed and negatively regulated by miR-146a-5p. Upregulation of miR-146a-5p can promote cell apoptosis and reduce autophagy of human and mouse chondrocytes by modulating the levels of cleaved caspase-3, cleaved PARP, Bax, Beclin 1, ATG5, p62, LC3-I, and LC3-II. Increasing the low level of NUMB reversed the effects of miR-146a-5p on chondrocyte apoptosis and autophagy. Intra-articular injection of miR-146a-5p antagomir can also reverse the effects of miR-146a-5p on the apoptosis and autophagy of knee joint chondrocytes in OA mice. Conclusion Downregulation of miR-146a-5p suppresses the apoptosis and promotes autophagy of chondrocytes by targeting NUMB in vivo and in vitro.

scholarly journals 1455. Potential Mechanisms of Cefiderocol MIC Increase in Enterobacterales in In Vitro Resistance Acquisition Studies

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S730-S730
Author(s):  
Yoshinori Yamano ◽  
Rio Nakamura ◽  
Miki Takemura ◽  
Roger Echols
Keyword(s):  
Iron Transport ◽  
Resistance Mechanisms ◽  
Altered Expression ◽  
Carbapenem Resistant ◽  
Mueller Hinton ◽  
Two Component ◽  
Mueller Hinton Agar ◽  
Related Proteins

Abstract Background Cefiderocol (CFDC) is a novel siderophore, iron-chelating cephalosporin, which is transported into bacteria via iron transporters. CFDC has potent in vitro and in vivo activity against all aerobic Gram-negative bacteria, including carbapenem-resistant strains. To date, clinical isolates with cefiderocol MIC >4 µg/mL have been found infrequently, in which the presence of a few β-lactamases or altered iron transport was found. We investigated potential new mechanisms causing CFDC MIC increases in non-clinical studies. Methods The mutation positions were determined by whole genome sequencing using four K. pneumoniae mutants including two KPC producers and one NDM producer that had shown CFDC MIC increases in previous in vitro resistance-acquisition studies. The mutant strains were obtained at the frequency of 10-7 to < 10-8 by spreading bacteria on standard Mueller‒Hinton agar medium containing CFDC at concentrations of 10× MIC, with or without apo-transferrin (20 μg/mL). CFDC MIC was determined by broth microdilution using iron-depleted cation-adjusted Mueller-Hinton broth based on Clinical and Laboratory Standards Institute guidelines. The emergence of MIC increase mutants was also assessed by in vitro chemostat models under humanized plasma pharmacokinetic exposures of CFDC. Results The possible resistance mechanisms were investigated. Mutation of baeS or envZ, sensors of two-component regulation systems, were found in three or two mutants among the tested four isolates, respectively, and caused the MIC to increase by 4–32-fold. The altered expression level of specific genes by the baeS or envZ mutation could affect CFDC susceptibility, but the specific genes have not been identified. In addition, the mutation of exbD, an accessory protein related to iron transport, was identified in one case and caused the MIC to increase by >8-fold. In vitro chemostat studies using two isolates (one NDM producer and one KPC producer) showed no resistance acquisition during 24-hour exposure. Table. Overview of mutation emergence in five isolates of K. pneumoniae Conclusion The mutation of two-component regulation systems (BaeSR and OmpR/EnvZ) and iron transport-related proteins were shown to be possible mechanisms causing CFDC MIC increases, but these mutants did not appear under human exposures. Disclosures Yoshinori Yamano, PhD, Shionogi & Co., Ltd. (Employee) Rio Nakamura, BSc, Shionogi & Co., Ltd. (Employee) Miki Takemura, MSc, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant)

Sign in / Sign up

Export Citation Format

Share Document