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  1. Article ; Online: COVID-19 implications for banks: evidence from an emerging economy.

    Barua, Bipasha / Barua, Suborna

    SN business & economics

    2020  Volume 1, Issue 1, Page(s) 19

    Abstract: The COVID-19 pandemic is damaging economies across the world, including financial markets and institutions in all possible dimensions. For banks in particular, the pandemic generates multifaceted crises, mostly through increases in default rates. This is ...

    Abstract The COVID-19 pandemic is damaging economies across the world, including financial markets and institutions in all possible dimensions. For banks in particular, the pandemic generates multifaceted crises, mostly through increases in default rates. This is likely to be worse in developing economies with poor financial market architecture. This paper utilizes Bangladesh as a case study of an emerging economy and examines the possible impacts of the pandemic on the country's banking sector. Bangladesh's banking sector already has a high level of non-performing loans (NPLs) and the pandemic is likely to worsen the situation. Using a state-designed stress testing model, the paper estimates the impacts of the COVID-19 pandemic on three particular dimensions-firm value, capital adequacy, and interest income-under different NPL shock scenarios. Findings suggest that all banks are likely to see a fall in risk-weighted asset values, capital adequacy ratios, and interest income at the individual bank and sectoral levels. However, estimates show that larger banks are relatively more vulnerable. The decline in all three dimensions will increase disproportionately if NPL shocks become larger. Findings further show that a 10% NPL shock could force capital adequacy of all banks to go below the minimum BASEL-III requirement, while a shock of 13% or more could turn it to zero or negative at the sectoral level. Findings call for immediate and innovative policy measures to prevent a large-scale and contagious banking crisis in Bangladesh. The paper offers lessons for other developing and emerging economies similar to Bangladesh.
    Language English
    Publishing date 2020-11-30
    Publishing country Switzerland
    Document type Journal Article
    ISSN 2662-9399
    ISSN (online) 2662-9399
    DOI 10.1007/s43546-020-00013-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: COVID-19 Implications for Banks

    Barua, Bipasha / Barua, Suborna

    SSRN Electronic Journal ; ISSN 1556-5068

    the Case of An Emerging Economy

    2020  

    Keywords covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    DOI 10.2139/ssrn.3646961
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Periodicities designed in the tropomyosin sequence and structure define its functions.

    Barua, Bipasha

    Bioarchitecture

    2013  Volume 3, Issue 3, Page(s) 51–56

    Abstract: Tropomyosin is an actin binding protein that regulates actin filament dynamics and its interactions with actin binding proteins such as myosin, tropomodulin, formin, Arp2/3 and ADF-cofilin in most eukaryotic cells. Tropomyosin is the prototypical two- ... ...

    Abstract Tropomyosin is an actin binding protein that regulates actin filament dynamics and its interactions with actin binding proteins such as myosin, tropomodulin, formin, Arp2/3 and ADF-cofilin in most eukaryotic cells. Tropomyosin is the prototypical two-chained, α-helical coiled coil protein that associates end-to-end and binds to both sides of the actin filament. Each tropomyosin molecule spans four to seven actin monomers in the filament, depending on the size of the tropomyosin. Tropomyosins have a periodic heptad repeat sequence that is characteristic of coiled coil proteins as well as additional periodicities required for its interaction with the actin filament, where each periodic repeat interacts with one actin molecule. This review addresses the role of periodic features of the Tm molecule in carrying out its universal functions of binding to the actin filament and its regulation and the specific features that may determine the isoform specificity of tropomyosins.
    MeSH term(s) Actins/chemistry ; Actins/metabolism ; Amino Acid Sequence ; Animals ; Humans ; Protein Binding ; Protein Structure, Secondary ; Tropomyosin/chemistry ; Tropomyosin/metabolism
    Chemical Substances Actins ; Tropomyosin
    Language English
    Publishing date 2013-07-08
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ISSN 1949-100X
    ISSN (online) 1949-100X
    DOI 10.4161/bioa.25616
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Tropomyosin Structure, Function, and Interactions: A Dynamic Regulator.

    Hitchcock-DeGregori, Sarah E / Barua, Bipasha

    Sub-cellular biochemistry

    2017  Volume 82, Page(s) 253–284

    Abstract: Tropomyosin is the archetypal-coiled coil, yet studies of its structure and function have proven it to be a dynamic regulator of actin filament function in muscle and non-muscle cells. Here we review aspects of its structure that deviate from canonical ... ...

    Abstract Tropomyosin is the archetypal-coiled coil, yet studies of its structure and function have proven it to be a dynamic regulator of actin filament function in muscle and non-muscle cells. Here we review aspects of its structure that deviate from canonical leucine zipper coiled coils that allow tropomyosin to bind to actin, regulate myosin, and interact directly and indirectly with actin-binding proteins. Four genes encode tropomyosins in vertebrates, with additional diversity that results from alternate promoters and alternatively spliced exons. At the same time that periodic motifs for binding actin and regulating myosin are conserved, isoform-specific domains allow for specific interaction with myosins and actin filament regulatory proteins, including troponin. Tropomyosin can be viewed as a universal regulator of the actin cytoskeleton that specifies actin filaments for cellular and intracellular functions.
    MeSH term(s) Amino Acid Sequence ; Animals ; Humans ; Protein Conformation ; Tropomyosin/chemistry ; Tropomyosin/ultrastructure
    Chemical Substances Tropomyosin
    Language English
    Publishing date 2017
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ISSN 0306-0225 ; 0096-8757
    ISSN 0306-0225 ; 0096-8757
    DOI 10.1007/978-3-319-49674-0_9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Myosin with hypertrophic cardiac mutation R712L has a decreased working stroke which is rescued by omecamtiv mecarbil.

    Snoberger, Aaron / Barua, Bipasha / Atherton, Jennifer L / Shuman, Henry / Forgacs, Eva / Goldman, Yale E / Winkelmann, Donald A / Ostap, E Michael

    eLife

    2021  Volume 10

    Abstract: Hypertrophic cardiomyopathies (HCMs) are the leading cause of acute cardiac failure in young individuals. Over 300 mutations throughout β-cardiac myosin, including in the motor domain, are associated with HCM. A β-cardiac myosin motor mutation (R712L) ... ...

    Abstract Hypertrophic cardiomyopathies (HCMs) are the leading cause of acute cardiac failure in young individuals. Over 300 mutations throughout β-cardiac myosin, including in the motor domain, are associated with HCM. A β-cardiac myosin motor mutation (R712L) leads to a severe form of HCM. Actin-gliding motility of R712L-myosin is inhibited, despite near-normal ATPase kinetics. By optical trapping, the working stroke of R712L-myosin was decreased 4-fold, but actin-attachment durations were normal. A prevalent hypothesis that HCM mutants are hypercontractile is thus not universal. R712 is adjacent to the binding site of the heart failure drug omecamtiv mecarbil (OM). OM suppresses the working stroke of normal β-cardiac myosin, but remarkably, OM rescues the R712L-myosin working stroke. Using a flow chamber to interrogate a single molecule during buffer exchange, we found OM rescue to be reversible. Thus, the R712L mutation uncouples lever arm rotation from ATPase activity and this inhibition is rescued by OM.
    MeSH term(s) Cardiomegaly/drug therapy ; Cardiotonic Agents/pharmacology ; Heart Failure/drug therapy ; Humans ; Mutation ; Urea/analogs & derivatives ; Urea/pharmacology ; Ventricular Myosins/chemistry ; Ventricular Myosins/genetics
    Chemical Substances Cardiotonic Agents ; omecamtiv mecarbil (2M19539ERK) ; Urea (8W8T17847W) ; Ventricular Myosins (EC 3.6.1.-)
    Language English
    Publishing date 2021-02-19
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2687154-3
    ISSN 2050-084X ; 2050-084X
    ISSN (online) 2050-084X
    ISSN 2050-084X
    DOI 10.7554/eLife.63691
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Myosin with hypertrophic cardiac mutation R712L has a decreased working stroke which is rescued by omecamtiv mecarbil

    Aaron Snoberger / Bipasha Barua / Jennifer L Atherton / Henry Shuman / Eva Forgacs / Yale E Goldman / Donald A Winkelmann / E Michael Ostap

    eLife, Vol

    2021  Volume 10

    Abstract: Hypertrophic cardiomyopathies (HCMs) are the leading cause of acute cardiac failure in young individuals. Over 300 mutations throughout β-cardiac myosin, including in the motor domain, are associated with HCM. A β-cardiac myosin motor mutation (R712L) ... ...

    Abstract Hypertrophic cardiomyopathies (HCMs) are the leading cause of acute cardiac failure in young individuals. Over 300 mutations throughout β-cardiac myosin, including in the motor domain, are associated with HCM. A β-cardiac myosin motor mutation (R712L) leads to a severe form of HCM. Actin-gliding motility of R712L-myosin is inhibited, despite near-normal ATPase kinetics. By optical trapping, the working stroke of R712L-myosin was decreased 4-fold, but actin-attachment durations were normal. A prevalent hypothesis that HCM mutants are hypercontractile is thus not universal. R712 is adjacent to the binding site of the heart failure drug omecamtiv mecarbil (OM). OM suppresses the working stroke of normal β-cardiac myosin, but remarkably, OM rescues the R712L-myosin working stroke. Using a flow chamber to interrogate a single molecule during buffer exchange, we found OM rescue to be reversible. Thus, the R712L mutation uncouples lever arm rotation from ATPase activity and this inhibition is rescued by OM.
    Keywords single molecule ; cardiac myosin ; optical trapping ; optical tweezers ; hypertrophic cardiomyopathy ; omecamtiv mecarbil ; Medicine ; R ; Science ; Q ; Biology (General) ; QH301-705.5
    Subject code 610
    Language English
    Publishing date 2021-02-01T00:00:00Z
    Publisher eLife Sciences Publications Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Distinct sites in tropomyosin specify shared and isoform-specific regulation of myosins II and V.

    Barua, Bipasha / Sckolnick, Maria / White, Howard D / Trybus, Kathleen M / Hitchcock-DeGregori, Sarah E

    Cytoskeleton (Hoboken, N.J.)

    2018  Volume 75, Issue 4, Page(s) 150–163

    Abstract: Muscle contraction, cytokinesis, cellular movement, and intracellular transport depend on regulated actin-myosin interaction. Most actin filaments bind one or more isoform of tropomyosin, a coiled-coil protein that stabilizes the filaments and regulates ... ...

    Abstract Muscle contraction, cytokinesis, cellular movement, and intracellular transport depend on regulated actin-myosin interaction. Most actin filaments bind one or more isoform of tropomyosin, a coiled-coil protein that stabilizes the filaments and regulates interactions with other actin-binding proteins, including myosin. Isoform-specific allosteric regulation of muscle myosin II by actin-tropomyosin is well-established while that of processive myosins, such as myosin V, which transport organelles and macromolecules in the cell periphery, is less certain. Is the regulation by tropomyosin a universal mechanism, the consequence of the conserved periodic structures of tropomyosin, or is it the result of specialized interactions between particular isoforms of myosin and tropomyosin? Here, we show that striated muscle tropomyosin, Tpm1.1, inhibits fast skeletal muscle myosin II but not myosin Va. The non-muscle tropomyosin, Tpm3.1, in contrast, activates both myosins. To decipher the molecular basis of these opposing regulatory effects, we introduced mutations at conserved surface residues within the six periodic repeats (periods) of Tpm3.1, in positions homologous or analogous to those important for regulation of skeletal muscle myosin by Tpm1.1. We identified conserved residues in the internal periods of both tropomyosin isoforms that are important for the function of myosin Va and striated myosin II. Conserved residues in the internal and C-terminal periods that correspond to Tpm3.1-specific exons inhibit myosin Va but not myosin II function. These results suggest that tropomyosins may directly impact myosin function through both general and isoform-specific mechanisms that identify actin tracks for the recruitment and function of particular myosins.
    MeSH term(s) Actins/chemistry ; Actins/metabolism ; Amino Acid Sequence ; Animals ; Cell Movement ; Chickens ; Mice ; Myosin Type II/chemistry ; Myosin Type II/metabolism ; Myosin Type V/chemistry ; Myosin Type V/metabolism ; Protein Binding ; Protein Conformation ; Protein Isoforms ; Rats ; Sequence Homology ; Tropomyosin/chemistry ; Tropomyosin/metabolism
    Chemical Substances Actins ; Protein Isoforms ; Tropomyosin ; Myosin Type II (EC 3.6.1.-) ; Myosin Type V (EC 3.6.1.-)
    Language English
    Publishing date 2018-03-26
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2534372-5
    ISSN 1949-3592 ; 1949-3584
    ISSN (online) 1949-3592
    ISSN 1949-3584
    DOI 10.1002/cm.21440
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Investigating the effects of tropomyosin mutations on its flexibility and interactions with filamentous actin using molecular dynamics simulation.

    Zheng, Wenjun / Hitchcock-DeGregori, Sarah E / Barua, Bipasha

    Journal of muscle research and cell motility

    2016  Volume 37, Issue 4-5, Page(s) 131–147

    Abstract: Tropomyosin (Tpm) is a two-chained α-helical coiled-coil protein that binds to filamentous actin (F-actin), and regulates its interactions with myosin by occupying three average positions on F-actin (blocked, closed, and open). Mutations in the Tpm are ... ...

    Abstract Tropomyosin (Tpm) is a two-chained α-helical coiled-coil protein that binds to filamentous actin (F-actin), and regulates its interactions with myosin by occupying three average positions on F-actin (blocked, closed, and open). Mutations in the Tpm are linked to heart diseases including hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). To elucidate the molecular mechanisms of Tpm mutations (including DCM mutation E54K, HCM mutations E62Q, A63V, K70T, V95A, D175N, E180G, L185R, E192K, and a designed synthetic mutation D137L) in terms of their effects on Tpm flexibility and its interactions with F-actin, we conducted extensive molecular dynamics simulations for the wild-type and mutant Tpm in complex with F-actin (total simulation time 160 ns per mutant). The mutants exhibited distinct changes (i.e., increase or decrease) in the overall and local flexibility of the Tpm coiled-coil, with each mutation causing both local and long-range modifications of the Tpm flexibility. In addition, our binding calculations revealed weakened Tpm-F-actin interactions (except for L185R, D137L and A63V) involving five periods of Tpm, which correlate with elevated fluctuation of Tpm relative to the blocked position on F-actin that may lead to easier activation and increased Ca
    Language English
    Publishing date 2016-10
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 283053-x
    ISSN 1573-2657 ; 0142-4319
    ISSN (online) 1573-2657
    ISSN 0142-4319
    DOI 10.1007/s10974-016-9447-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Positive cardiac inotrope omecamtiv mecarbil activates muscle despite suppressing the myosin working stroke

    Michael S. Woody / Michael J. Greenberg / Bipasha Barua / Donald A. Winkelmann / Yale E. Goldman / E. Michael Ostap

    Nature Communications, Vol 9, Iss 1, Pp 1-

    2018  Volume 11

    Abstract: Omecamtiv mecarbil (OM) is a positive cardiac inotrope in clinical trials for the treatment of heart failure whose mechanism of action is incompletely understood. Here the authors show that OM inhibits myosin's working stroke and prolongs actomyosin ... ...

    Abstract Omecamtiv mecarbil (OM) is a positive cardiac inotrope in clinical trials for the treatment of heart failure whose mechanism of action is incompletely understood. Here the authors show that OM inhibits myosin's working stroke and prolongs actomyosin attachment and propose a model that reconciles the OM-induced increase in cardiac performance in vivo with the inhibitory actions observed in vitro.
    Keywords Science ; Q
    Language English
    Publishing date 2018-09-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Positive cardiac inotrope omecamtiv mecarbil activates muscle despite suppressing the myosin working stroke

    Michael S. Woody / Michael J. Greenberg / Bipasha Barua / Donald A. Winkelmann / Yale E. Goldman / E. Michael Ostap

    Nature Communications, Vol 9, Iss 1, Pp 1-

    2018  Volume 11

    Abstract: Omecamtiv mecarbil (OM) is a positive cardiac inotrope in clinical trials for the treatment of heart failure whose mechanism of action is incompletely understood. Here the authors show that OM inhibits myosin's working stroke and prolongs actomyosin ... ...

    Abstract Omecamtiv mecarbil (OM) is a positive cardiac inotrope in clinical trials for the treatment of heart failure whose mechanism of action is incompletely understood. Here the authors show that OM inhibits myosin's working stroke and prolongs actomyosin attachment and propose a model that reconciles the OM-induced increase in cardiac performance in vivo with the inhibitory actions observed in vitro.
    Keywords Science ; Q
    Language English
    Publishing date 2018-09-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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