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Red Blood Cell and Platelet Mechanics
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
The platelet cytoskeleton consists of three major components: a spectrin-based skeleton adherent to the plasma membrane, microtubule coils (marginal band) along the perimeter, and the cytoplasmic actin network. Actin is the most abundant protein, with 2 × 106 molecules per platelet. Approximately 800,000 actin monomers assemble to form 2000–4000 actin filaments (Hartwig and DeSisto 1991). The crosslinker protein filamin A was shown to be important for controlling the distribution of the GPIb-V-IX receptor on the platelet surface and attaching it to the actin cytoskeleton (Nakamura et al. 2006). On activation, platelets rearrange their cytoskeleton with the help of cytoskeletal-regulatory proteins (such as gelsolin, cofilin, profilin, Arp2/3, Wiskott–Aldrich Syndrome protein (WASP), and CapZ), change their discoid form to spherical shape, and tether the integrin αIIbβ3 to the underlying, newly assembled actin filaments. Finally, cytoplasmic myosin binds to actin polymers and applies contractile forces (Cove and Crawford 1975). In general, the platelet has turned out be a good model to study mechanobiological questions, since platelets are anucleated cells, have a high actin content, and highly express mechanical-relevant receptors, such as integrins (αIIbβ3: 80,000 copies), on a small surface (Ciciliano et al. 2014).
S100B protein: general characteristics and pathophysiological implications in the Central Nervous System
Published in International Journal of Neuroscience, 2022
Ana Cristina Arrais, Lívia Helena M. F. Melo, Bianca Norrara, Marina Abuquerque B. Almeida, Kalina Fernandes Freire, Acydalia Madruga M. F. Melo, Lucidio Clebeson de Oliveira, Francisca Overlânia Vieira Lima, Rovena Clara G. J. Engelberth, Jeferson de Souza Cavalcante, Dayane Pessoa de Araújo, Fausto Pierdoná Guzen, Marco Aurelio M. Freire, José Rodolfo L. P. Cavalcanti
S100B is involved in regulatory activities both intra and extracellularly, exerting its biological function interacting with other proteins, directly influencing the activity of these cells. With respect to its intracellular actions, it acts making regulatory effects on cell proliferation, shape, and differentiation, as well as energetic metabolism (42), enzymatic activation via interaction with cytoplasmic cytoskeletal proteins such as glial fibrillar acid protein (GFAP) and CAPz (43), as well as protein phosphorylation, transcription and homeostasis of Ca2+ (21). GFAP, in particular, is a constitutive protein of macroglial cells in the CNS that regulates brain homeostasis in both normal and altered states. Since astrocytes are activated following disturbances in the normal physiology of the CNS (44–49), its regulation by S100B can be associated with an increase in the pro-inflammatory cytokines release through NF-kβ and p38 MAPK signaling (50).
Effects of homocysteine and memantine on oxidative stress related TRP cation channels in in-vitro model of Alzheimer’s disease
Published in Journal of Receptors and Signal Transduction, 2021
İshak Suat Övey, Mustafa Nazıroğlu
Stock solution of the AP-18, N-(p-amylcinnamoyl) Anthranilic acid (ACA), CapZ, CAPSN and CIN were prepared in DMSO and they were diluted into appropriate concentrations. TRPA1 was gated by adding extracellular CIN (0.1 mM), and the channel was inhibited extracellular administration of AP-18 (0.02 mM) into extracellular buffer. TRPM2 was gated by adding extracellular CumPx (0.1 mM), and it was extracellularly inhibited by ACA (0.025 mM). TRPV1 was gated by adding extracellular CAPSN (0.1 mM), and it was extracellularly inhibited by CapZ (0.1 mM).