Autophagy plays important roles in metabolism, differentiation, and survival in T cells. TNFAIP3/A20 is a ubiquitin-editing enzyme that is thought to be a negative regulator of autophagy in cell lines. However, the role of TNFAIP3 in autophagy remains unclear. To determine whether TNFAIP3 regulates autophagy in CD4 T cells, we first analyzed Tnfaip3-deficient naïve CD4 T cells in vitro. We demonstrated that Tnfaip3-deficient CD4 T cells exhibited reduced MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3) puncta formation, increased mitochondrial content, and exaggerated reactive oxygen species (ROS) production. These results indicate that TNFAIP3 promotes autophagy after T cell receptor (TCR) stimulation in CD4 T cells. We then investigated the mechanism by which TNFAIP3 promotes autophagy signaling. We found that TNFAIP3 bound to the MTOR (mechanistic target of rapamycin) complex and that Tnfaip3-deficient cells displayed enhanced ubiquitination of the MTOR complex and MTOR activity. To confirm the effects of enhanced MTOR activity in Tnfaip3-deficient cells, we analyzed cell survival following treatment with Torin1, an MTOR inhibitor. Tnfaip3-deficient CD4 T cells exhibited fewer cell numbers than the control cells in vitro and in vivo. In addition, the impaired survival of Tnfaip3-deficient cells was ameliorated with Torin1 treatment in vitro and in vivo. The effect of Torin1 was abolished by Atg5 deficiency. Thus, enhanced MTOR activity regulates the survival of Tnfaip3-deficient CD4 T cells. Taken together, our findings illustrate that TNFAIP3 restricts MTOR signaling and promotes autophagy, providing new insight into the manner in which MTOR and autophagy regulate survival in CD4 T cells.

Ubiquitination is a crucial post-translational modification; however, the functions of ubiquitin-coding genes remain unclear. UBA52 encodes a fusion protein comprising ubiquitin at the N-terminus and ribosomal protein L40 (RPL40) at the C-terminus. Here we showed that Uba52-deficient mice die during embryogenesis. UBA52-deficient cells exhibited normal levels of total ubiquitin. However, UBA52-deficient cells displayed decreased protein synthesis and cell-cycle arrest. The overexpression of UBA52 ameliorated the cell-cycle arrest caused by UBA52 deficiency. Surprisingly, RPL40 expression itself is insufficient to regulate cyclin D expression. The cleavage of RPL40 from UBA52 was required for maintaining protein synthesis. Furthermore, we found that RPL40 formed a ribosomal complex with ubiquitin cleaved from UBA52. UBA52 supplies RPL40 and ubiquitin simultaneously to the ribosome. Our study demonstrated that the ubiquitin-coding gene UBA52 is not just an ubiquitin supplier to the ubiquitin pool but is also a regulator of the ribosomal protein complex. These findings provide novel insights into the regulation of ubiquitin-dependent translation and embryonic development.

Mixed monolayers consisting of octakis(octadecyloxy)phthalocyanine metal complexes (C18PcM; M ) Mg, Co, Cu, Zn) and long-chain alkanes on a water surface were investigated by measurements of π-A isotherms and visible absorption spectra and Brewster angle microscopy observation. C18PcCu and octadecane (C18) in a 1:7 molar ratio gave a uniform monolayer, where phthalocyanine rings float in parallel with a water surface, and one C18PcCu molecule incorporates seven C18 molecules to form a molecular complex. It was found that the formation of two-dimensional molecular complexes consisting of C18PcCu and a long-chain alkane shows critical temperature dependence, reflecting the melting point of guest hydrocarbons.

A water‐soluble stilbene derivative with cationic charges enables tuning of the dispersibility of the single‐walled carbon nanotubes (SWNTs) in aqueous solution by photoirradiation. The nearly coplanar core of the stilbene dispersant interacts with the SWNTs via π–π interactions, resulting in a stable dispersion of the SWNTs. Photoinduced cyclization for the dispersant‐triggered reprecipitation of the SWNTs is due to detachment of the dispersant from SWNTs surfaces.

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N-(L-valyl-L-valyl-L-valyl)azobenzene-4-carboxamide [Azo(LVal)(3)] is a low molecular weight gelator that forms a photofunctional fibrous assembled system; this assembly undergoes dispersion/reorganization upon trans-to-cis photoisomerization, which, as a result of the breaking and reforming of hydrogen bonds, induces reversible sol-gel transitions. In this paper, we describe the mechanism by which azobenzene isomerization induces the breaking and reorganization of these assembled systems. We applied Fourier transform infrared spectroscopy to investigate the effect of the irradiation time on the change in absorption intensity in the amide I region. The lifetime of the cis isomer influences the photoinduced breaking and reforming of hydrogen bonds between trivalyl units. Because the cis isomer of Azo(LVal)(3) had a long lifetime, its assemblies underwent reversible phototriggered dispersion and organization. In contrast, the lifetime of the cis isomer of 4'-dimethylamino-N-(L-valyl-L-valyl-L-valyl)azobenzene-4-carboxamide [pMR(LVal)(3)] was too short to disrupt the hydrogen bonds in its fibrous self-assembled system.