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- Cuéllar, J., et al.
(författare)
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The Molecular Chaperone CCT Sequesters Gelsolin and Protects it from Cleavage by Caspase-3: CCT-Gelsolin interaction may affect actin dynamics
- 2022
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836. ; 434:5
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Tidskriftsartikel (refereegranskat)abstract
- The actin filament severing and capping protein gelsolin plays an important role in modulation of actin filament dynamics by influencing the number of actin filament ends. During apoptosis, gelsolin becomes constitutively active due to cleavage by caspase-3. In non-apoptotic cells gelsolin is activated by the binding of Ca2+. This activated form of gelsolin binds to, but is not a folding substrate of the molecular chaperone CCT/TRiC. Here we demonstrate that in vitro, gelsolin is protected from cleavage by caspase-3 in the presence of CCT. Cryoelectron microscopy and single particle 3D reconstruction of the CCT:gelsolin complex reveals that gelsolin is located in the interior of the chaperonin cavity, with a placement distinct from that of the obligate CCT folding substrates actin and tubulin. In cultured mouse melanoma B16F1 cells, gelsolin co-localises with CCT upon stimulation of actin dynamics at peripheral regions during lamellipodia formation. These data indicate that localised sequestration of gelsolin by CCT may provide spatial control of actin filament dynamics. © 2021 The Authors
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| 2. |
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| 3. |
- Sloboda, Tamara, et al.
(författare)
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Unravelling the ultrafast charge dynamics in PbS quantum dots through resonant Auger mapping of the sulfur K-edge
- 2022
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 12:49, s. 31671-31679
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Tidskriftsartikel (refereegranskat)abstract
- There is a great fundamental interest in charge dynamics of PbS quantum dots, as they are promising for application in photovoltaics and other optoelectronic devices. The ultrafast charge transport is intriguing, offering insight into the mechanism of electron tunneling processes within the material. In this study, we investigated the charge transfer times of PbS quantum dots of different sizes and non-quantized PbS reference materials by comparing the propensity of localized or delocalized decays of sulfur 1s core hole states excited by X-rays. We show that charge transfer times in PbS quantum dots decrease with excitation energy and are similar at high excitation energy for quantum dots and non-quantized PbS. However, at low excitation energies a distinct difference in charge transfer time is observed with the fastest charge transfer in non-quantized PbS and the slowest in the smallest quantum dots. Our observations can be explained by iodide ligands on the quantum dots creating a barrier for charge transfer, which reduces the probability of interparticle transfer at low excitation energies. The probability of intraparticle charge transfer is limited by the density of available states which we describe according to a wave function in a quantum well model. The stronger quantum confinement effect in smaller PbS quantum dots is manifested as longer charge transfer times relative to the larger quantum dots at low excitation energies.
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