| 1. |
- Tararuk, Tatsiana, et al.
(författare)
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JNK1 phosphorylation of SCG10 determines microtubule dynamics and axodendritic length
- 2006
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 173:2, s. 265-277
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Tidskriftsartikel (refereegranskat)abstract
- c-Jun NH2-terminal kinases (JNKs) are essential during brain development, when they regulate morphogenic changes involving cell movement and migration. In the adult, JNK determines neuronal cytoarchitecture. To help uncover the molecular effectors for JNKs in these events, we affinity purified JNK-interacting proteins from brain. This revealed that the stathmin family microtubule-destabilizing proteins SCG10, SCLIP, RB3, and RB3′ interact tightly with JNK. Furthermore, SCG10 is also phosphorylated by JNK in vivo on sites that regulate its microtubule depolymerizing activity, serines 62 and 73. SCG10-S73 phosphorylation is significantly decreased in JNK1−/− cortex, indicating that JNK1 phosphorylates SCG10 in developing forebrain. JNK phosphorylation of SCG10 determines axodendritic length in cerebrocortical cultures, and JNK site–phosphorylated SCG10 colocalizes with active JNK in embryonic brain regions undergoing neurite elongation and migration. We demonstrate that inhibition of cytoplasmic JNK and expression of SCG10-62A/73A both inhibited fluorescent tubulin recovery after photobleaching. These data suggest that JNK1 is responsible for regulation of SCG10 depolymerizing activity and neurite elongation during brain development.
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| 2. |
- Wang, Hongdong, et al.
(författare)
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Superlubricity of Polyalkylene Glycol Aqueous Solutions Enabled by Ultrathin Layered Double Hydroxide Nanosheets
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 11:22, s. 20249-20256
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Tidskriftsartikel (refereegranskat)abstract
- It was previously proved that the existence of a large amount of hydrogen ions in water-based lubricants can easily lead to a superlubric state; however, it was also shown that these hydrogen ions could cause severe corrosion. As part of a large family of attractive clays, layered double hydroxides (LDHs) possess excellent tribological properties in water-based lubrication systems. In the present work, two different kinds of LDHs are dispersed in polyalkylene glycol (PAG) aqueous solutions, in two distinct forms: ultrathin nanosheets (ULDH-NS) of ca. 60 nm wide and ca. 1 nm thick (single or double layer) and nanoparticles (LDH-NP) of ca. 19.73 nm wide and ca. 8.68 nm thick. We find that the addition of ULDH-NS greatly shortens (as much as 85%) the running-in period prior to reaching the superlubricity regime and increases the ultimate load-bearing capacity by about four times. As compared to the fluid film thickness of the lubricating PAG solution, their ultrathin longitudinal dimension will not impair or influence the fluid film coverage in the contact zone. The analysis of sliding solid surfaces and the atomic force microscope microscale friction test demonstrate that the adsorption of ULDH-NS enables the sliding solid surfaces to be polished and protected because of their relatively weak interlayer interaction and increased adhesion effect. Owing to their superior tribological properties as lubricant additives, ultrathin LDH nanosheets hold great potential for enabling liquid superlubricity in industrial applications in the future.
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| 3. |
- Yu, Guimei, et al.
(författare)
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Structure of Arabidopsis SOQ1 lumenal region unveils C-terminal domain essential for negative regulation of photoprotective qH
- 2022
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Ingår i: Nature Plants. - : Nature Publishing Group. - 2055-0278. ; 8:7, s. 840-855
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Tidskriftsartikel (refereegranskat)abstract
- Non-photochemical quenching (NPQ) plays an important role for phototrophs in decreasing photo-oxidative damage. qH is a sustained form of NPQ and depends on the plastid lipocalin (LCNP). A thylakoid membrane-anchored protein SUPPRESSOR OF QUENCHING1 (SOQ1) prevents qH formation by inhibiting LCNP. SOQ1 suppresses qH with its lumen-located thioredoxin (Trx)-like and NHL domains. Here we report structural data, genetic modification and biochemical characterization of Arabidopsis SOQ1 lumenal domains. Our results show that the Trx-like and NHL domains are associated together, with the cysteine motif located at their interface. Residue E859, required for SOQ1 function, is pivotal for maintaining the Trx–NHL association. Importantly, the C-terminal region of SOQ1 forms an independent β-stranded domain that has structural homology to the N-terminal domain of bacterial disulfide bond protein D and is essential for negative regulation of qH. Furthermore, SOQ1 is susceptible to cleavage at the loops connecting the neighbouring lumenal domains both in vitro and in vivo, which could be a regulatory process for its suppression function of qH.
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| 4. |
- Yu, Guimei, et al.
(författare)
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Structure of SOQ1 lumenal domains identifies potential disulfide exchange for negative regulation of photoprotection, qH
- 2024
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Non-photochemical quenching (NPQ) plays an important role for phototrophs in decreasing photo-oxidative damage. qH is a sustained component of NPQ and depends on the plastid lipocalin (LCNP). A thylakoid membrane-anchored protein SUPPRESSOR OF QUENCHING1 (SOQ1) prevents qH formation by inhibiting LCNP. SOQ1 suppresses qH with its lumen-located C-terminal Trx-like and NHL domains. Here we report crystal structures and biochemical characterization of SOQ1 lumenal domains. Our results show that the Trx-like and NHL domains are stably associated, with the potential redox-active motif located at their interface. Residue E859 essential for SOQ1 function is pivotal for mediating the inter-domain interaction. Moreover, the C-terminal region of SOQ1 forms an independent β-stranded domain, which possibly interacts with the Trx-like domain through disulfide exchange. Furthermore, SOQ1 is susceptible to cleavage at the loops connecting the neighboring domains both in vitro and in vivo, which could be a regulatory process for its suppression function of qH.
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| 5. |
- Yu, Xiaolin, et al.
(författare)
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Heparan sulfate-dependent phase separation of CCL5 and its chemotactic activity
- 2024
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Secreted chemokines form concentration gradients in target tissues to control migratory directions and patterns of immune cells in response to inflammatory stimulation; however, how the gradients are formed is much debated. Heparan sulfate (HS) binds to chemokines and modulates their activities. In this study, we investigated the roles of HS in the gradient formation and chemoattractant activity of CCL5 that is known to bind to HS. CCL5 and heparin underwent liquid-liquid phase separation and formed gradient, which was confirmed using CCL5 immobilized on heparin-beads. The biological implication of HS in CCL5 gradient formation was established in CHO-K1 (wild-type) and CHO-677 (lacking HS) cells by Transwell assay. The effect of HS on CCL5 chemoattractant activity was further proved by Transwell assay of human peripheral blood cells. Finally, peritoneal injection of the chemokines into mice showed reduced recruitment of inflammatory cells either by mutant CCL5 (lacking heparin-binding sequence) or by addition of heparin to wild-type CCL5. Our experimental data propose that co-phase separation of CCL5 with HS establishes a specific chemokine concentration gradient to trigger directional cell migration. The results warrant further investigation on other heparin-binding chemokines and allows for a more elaborate insight into disease process and new treatment strategies.
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