Interleukin-2 (IL-2)-dependent T cell clone CTLL-2 underwent apoptosis by deprivation of IL-2 from culture medium. The decrease in the anti-apoptotic Bcl-X L protein level was observed during apoptosis after IL-2 withdrawal. We found that Bcl-X L protein was cleaved to produce two 18 kDa fragments during CTLL-2 cell apoptosis. When the activation of caspases was suppressed by overexpressing human Bcl-2 protein or by the addition of caspase inhibitors, cleavage of Bcl-X L protein was suppressed in vivo. Bcl-X L protein cleavage by incubation with apoptosed CTLL-2 cell lysate was suppressed by the caspase-3/CPP32-speci®c tetrapeptide inhibitor in vitro. Therefore, caspase-3/CPP32-like proteases were activated and involved in the cleavage of Bcl-X L protein during CTLL-2 cell apoptosis. We found that Bcl-X L protein was cleaved by caspase-3/ CPP32 at two sites in the loop domain (i.e., HLAD A). The transfection of the carboxy-terminal 18 kDa Bcl-X L fragment increased the sensitivity to apoptosis. These results indicate that caspase-3/CPP32-like proteases cleaved anti-apoptotic Bcl-X L protein and resulted in accelerated apoptotic cell death.

The distinct piezochromic luminescent responses of chargeÀtransfer inclusion crystals, which consist of small aromatic guest molecules with naphthalenediimide derivatives, are reported. Reversible multichromism is observed over the entire visible region in response to high pressure, whereas a weak response to mechanical grinding is evident. High-pressure single-crystal X-ray diffraction analysis and TD-DFT calculations clearly suggest that high compression induces a closer arrangement with a short interfacial distance between small aromatic guest molecules and naphthalenediimide derivatives, which is proposed as the origin of the drastic luminescent color change.The development of luminescent molecules that are sensitive to external stimuli has attracted considerable attention in recent years owing to their potential applications, such as in bioimaging, display, memory, and sensors. [1,2] Materials sensitive to external stimuli, such as pH, light, and temperature, have been relatively well investigated, whereas piezochromic luminescent materials, which change their luminescence upon mechanical grinding/shearing or high compression, remain poorly understood. Indeed, a number of mechanochromic systems, based on organic molecules [3] and metal complexes, [4] have been developed. In early stages of research, high-pressure effects on the electrostatic structure of organic crystals such as anthracene, chrysene, and pyrene were reported. [5] Based on the recent advance in understanding the mechanochromic systems, Zou, Tian and co-workers have reported anthracenederivatives, which exhibit mechanochromism after mechanical grinding and high pressure. [3a] In 2013, Saito, Yamaguchi and co-workers reported a propeller-shaped tetrathiazoylthiophene whose luminescence displayed distinct emission color changes in response to mechanical grinding and high pressure. [3c] Intramolecular charge-transfer (CT) fluorophores with an electron acceptor (A) and an electron donor (D) were used to demonstrate photoluminescence color changes in response to mechanical grinding and high pressure. In the molecular designs, intramolecular rotation of phenyl rings and packing modes, such as p-p stacked aggregates or amorphous states, are essential to tune the emission properties. However, the organic molecules that have been reported so far possess a major drawback. Most of the organic molecules that exhibit mechanochromism show the change of molecular packing modes and molecular torsion angles based on monomer emission, excimer emission, and intramolecular CT emission. Therefore, when grinding or smashing to make the crystal smaller, the crystal structure unexpectedly changes or collapses to form an amorphous powder. It is necessary to use pristine crystals when evaluating the piezochromic properties against high pressure. To the best of our knowledge, organic molecules that show a weak fluorescence response to mechanical grinding/smashing (anisotropic pressure) but significant response to high pressure (quasi-isotropic pressure) are rare.A...

What was the most significant result of this study?We found ad istinctive piezochromic luminescent response of as eries of intermolecularc harge-transfer crystals and their structural properties are investigated. High-pressure singlecrystal X-ray analysis and TD-DFT calculations clearly suggested that the piezochromic properties are observedb ythe closer arrangement of interfacial distances between charge-transfer crystalsi nduced by high compression. In particular,o ur charge-transfer crystalss how an unusual multichromic feature in which the piezochromic response is reversibly controlled by high pressure over the entire visible region (over 100 nm), whereas the effect of mechanical grinding is negligible. Who designed the cover?This cover artworki sd esigned by Ms. Aria Hisaeda.S he understood our vague image request and drew aw onderful coverThe front cover artwork is provided by the group of Prof. Y. Hisaeda at KyushuU niversity (Japan). The work is in collaboration with the group of Prof. M. Abe and Prof.Y .

The Front Cover illustrates the distinct piezochromic response of charge‐transfer inclusion crystals, which consist of small aromatic guest molecules with naphthalenediimide derivatives. Reversible multichromism is observed over the entire visible region in response to high pressure using a diamond anvil cell, whereas a weak response to mechanical grinding is evident. More information can be found in the Communication by T. Ono et al. on page 416 in Issue 5, 2018 (DOI: 10.1002/cptc.201700227).