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Abstract: In order to clarify the intrinsic bulk electronic structure of La1−xSrxMnO3 (LSMO) thin films, we have performed high-energy ( keV) synchrotron photoemission spectroscopy (PES) of Mn 2p core-levels. In sharp contrast with the previous soft X-ray PES (–1486.6 eV), the high-energy PES spectra exhibit a clear additional peak at the low binding-energy side of the Mn 2 peak. To check for surface sensitivity, we measured take-off-angle dependence of Mn 2p core-levels. The results indicate that this additional peak originates from the bulk electronic structure. The peak shows a noticeable increase in the metallic phase of LSMO for and 0.4, indicating that the origin of this peak is strongly related to the metallic physical properties of LSMO thin films. A single ion () cluster calculation including charge transfer from doping-induced states reproduces the new bulk-derived feature observed in Mn 2p core-levels. [Copyright &y& Elsevier]

The lysophosphatidylserine (LysoPS) receptor P2Y10, also known as LPS 2 , plays crucial roles in the regulation of immune responses and holds promise for the treatment of autoimmune diseases. Here, we report the cryoelectron microscopy (cryo-EM) structure of LysoPS-bound P2Y10 in complex with an engineered G 13 heterotrimeric protein. The structure and a mutagenesis study highlight the predominant role of a comprehensive polar network in facilitating the binding and activation of the receptor by LysoPS. This interaction pattern is preserved in GPR174, but not in GPR34. Moreover, our structural study unveils the essential interactions that underlie the Gα 13 engagement of P2Y10 and identifies key determinants for Gα 12 -vs.-Gα 13 -coupling selectivity, whose mutations selectively disrupt Gα 12 engagement while preserving the intact coupling of Gα 13 . The combined structural and functional studies provide insights into the molecular mechanisms of LysoPS recognition and Gα 12/ 13 coupling specificity., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

G-protein-coupled receptors (GPCRs) transduce diverse signals into the cell by coupling to one or several Gα subtypes. Of the 16 Gα subtypes in human cells, Gα 12 and Gα 13 belong to the G 12 subfamily and are reported to be functionally different. Notably, certain GPCRs display selective coupling to either Gα 12 or Gα 13 , highlighting their significance in various cellular contexts. However, the structural basis underlying this selectivity remains unclear. Here, using a Gα 12 -coupled designer receptor exclusively activated by designer drugs (DREADD; G 12 D) as a model system, we identified residues in the α5 helix and the receptor that collaboratively determine Gα 12 -vs-Gα 13 selectivity. Residue-swapping experiments showed that G 12 D distinguishes differences between Gα 12 and Gα 13 in the positions G.H5.09 and G.H5.23 in the α5 helix. Molecular dynamics simulations observed that I378 G.H5.23 in Gα 12 interacts with N103 2.39 , S169 3.53 and Y176 34.53 in G 12 D, while H364 G.H5.09 in Gα 12 interact with Q264 5.71 in G 12 D. Screening of mutations at these positions in G 12 D identified G 12 D mutants that enhanced coupling with Gα 12 and to an even greater extent with Gα 13 . Combined mutations, most notably the dual Y176 34.53 H and Q264 5.71 R mutant, further enhanced Gα 12 / 13 coupling, thereby serving as a potential Gα 12/13 -DREADD. Such novel Gα 12/13 -DREADD may be useful in future efforts to develop drugs that target Gα 12/13 signaling as well as to identify their therapeutic indications., (© 2024. The Author(s).)

Polo-like kinase 1 (Plk1) is a mitotic kinase that has multiple functions throughout the cell cycle. Catalytic activation of Plk1 is known to be regulated by phosphorylation of the kinase domain, including Thr210, and by releasing the kinase domain from its inhibitory polo-box domain. However, how Plk1 is activated to fulfill its proper roles, in time and space, is not well understood. In this study, we unintentionally found that the expression of a constitutively active form of human Plk1 is toxic to bacterial cells, such that cells contained point mutations that alleviate the kinase activity. Structural prediction revealed that these mutations are adjacent to the amino acids supporting the kinase activity. When human cells express these mutants, we found decreased levels of Plk1's substrate phosphorylation, resulting in mitotic defects. Moreover, unlike in bacterial cells, the expression of activated Plk1 mutants did not affect cell proliferation in human cells unless localized at the right place in mitosis. Our observations identified new suppressor mutations and underscored the importance of spatiotemporal regulation in Plk1, providing a basis for how we might intervene in this kinase for therapeutic purpose in human cells., (© 2023 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.)

Cancer stem cells have the capability of self-renewal and multipotency and are, therefore, associated with tumor heterogeneity, resistance to chemoradiation therapy, and metastasis. The hypothesis that multinucleated giant cells, which often emerge following chemo- and/or radiotherapy, serve as cancer stem cells has not been fully evaluated. Although a previous study demonstrated that these cells functioned as stem cells, only low levels of Yamanaka factors were expressed, contrasting with the high expression seen from their gestated first-generation mononuclear cells. Herein, we report a case of a plasmablastic neoplasm with multinucleated giant cells that were analyzed for stemness to test the above hypothesis. The patient was a male in his 80s who had a plasmablastic neoplasm that was not easily distinguishable as plasmablastic lymphoma versus plasma cell myeloma of plasmablastic type. Lymph node biopsy showed predominant mononuclear cell proliferation with admixed multinucleated giant cells. Immunohistochemistry and in situ hybridization showed that both multinucleated and mononuclear cells had the same profile: CD138(+), light chain restriction of κ>λ, cyclin D1(+), CD68(-), EBER-ISH (+). These results suggested that both cell types were neoplastic. In accordance with the previous study, the multinucleated giant cells showed low expression of Yamanaka factors, which were highly expressed in some of the mononuclear cells. Furthermore, the multinucleated giant cells showed a much lower proliferative activity (Mib1/Ki67 index) than the mononuclear cells. Based on these results, the multinucleated giant cells were compatible with cancer stem cells. This case is expected to expand the knowledge base regarding biology of cancer stem cells., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Otsuka-Kamakura, Sugiura, Yamazaki, Shimizu and Hiruta.)

Hydroxyl radicals generate a broad range of DNA lesions in living cells. Cyclopurine deoxynucleosides (CPUs) are a biologically significant class of oxidative DNA lesions due to their helical distortion and chemically stability. The CPUs on DNA are substrates for the nucleotide excision repair (NER) but not for base excision repair or direct damage reversal. Moreover, these lesions block DNA and RNA polymerases, resulting in cell death. Here, we describe the chemical synthesis of 5'S and 5'R isomers of 5',8-cyclodeoxyadenosine triphosphate (cdATP) and demonstrate their ability to be incorporated into DNA by replicative DNA polymerases. DNA synthesis assays revealed that the incorporation of the stereoisomeric cdATPs strongly inhibits DNA polymerase reactions. Surprisingly, the two stereoisomers had different mutagenic profiles, since the S isomer of cdATP could be inserted opposite to the dTMP, but the R isomer of cdATP could be inserted opposite to the dCMP. Kinetic analysis revealed that the S isomer of cdATP could be incorporated more efficiently (25.6 μM(-1) min(-1)) than the R isomer (1.13 μM(-1) min(-1)) during DNA synthesis. Previous data showed that the S isomer in DNA blocked DNA synthesis and the exonuclease activity of DNA polymerase and is less efficiently repaired by NER. This indicates that the S isomer has a tendency to accumulate on the genome DNA, and as such, the S isomer of cdATP may be a candidate cytotoxic drug.

Itinerant ferromagnetism derived from e(g) and t(2g) states has been studied by the Gutzwiller variational method based on the two-band Hubbard model. The analysis shows that the magnetization value that depends on the orbital reflects strength of renormalization for each band. As a result, the magnetization of the 3d(t(2g)) band, which is more strongly renormalized in the calculation, has a larger value than that of the 3d(e(g)) band. By changing the atomic interaction and projected orbital density of states (DOS), we have discussed general tendencies that the magnetizations by the e(g) and t(2g) states are determined by the relative intensities of the projected orbital DOS at the Fermi energy, the renormalized kinetic energies relative to U, and stability of atomic multielectron configuration states. The result indicates that increases in Coulomb interaction U and the portion of Hund's coupling J in the atomic interaction lead to balanced magnetizations between the two states. Variation in the above factors can generate a variety of spin-dependent electronic structures near the Fermi energy in 3d transition metal ferromagnets.

Integrin-binding sialoprotein (IBSP) is a member of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family; and the whole SIBLING family is further included in a larger secretory calcium-binding phosphoprotein (SCPP) family. SIBLING proteins are known to construct a part of the non-collagenous extracellular matrices of calcified tissues, and considered to have arisen by duplication and subsequent divergent evolution of a single ancient gene. To understand the alterations of SIBLING molecules associated with the evolution of calcified tissues in vertebrates, we initiated a search for lower vertebrate orthologs of SIBLING genes. In the present study, an IBSP ortholog from a reptile (caiman) and two distinct orthologs from an amphibian (African clawed toad) were identified and characterized. As expected, the toad IBSP genes were transcribed only in calcified tissue (jaw and tibia), as also seen in mammals. The caiman, toad, avian, and mammalian IBSPs share several unique features specific for IBSP and apparently have similar properties. Furthermore, analysis of the sequences suggested that the IBSP molecule might have gradually intensified its functions related to calcification during its evolutionary process through tetrapods.

Matrix metalloproteinase-20 (MMP20; enamelysin) is important for proteolytic processing of extracellular matrix (ECM) proteins during the formation of enamel and plays a critical role in proteolytic processing of amelogenin (AMEL), the most abundant enamel ECM protein. MMP20 might have played a role in the emergence of teeth, because jawless vertebrates with primordial teeth on their external skeletons may have possessed the MMP20 gene, and MMP20 and enamel ECM proteins are thought to have evolved together in a special relationship over time. Thus, an understanding of the molecular evolution of the MMP20 gene is important for elucidating the evolution of enamel and it is necessary to identify the orthologs of the MMP20 gene in non-mammals, as it has been identified in mammals. In the present study, orthologs of the MMP20 genes from a reptile (caiman) and an amphibian (African clawed toad) were cloned and characterized. Comparisons of the orthologs revealed that the MMP20 proteins were highly conserved throughout the evolution of tetrapods. Further, the caiman, toad, and mammalian MMP20 shared several unique features specific for MMP20, but not for other matrix metalloproteinases. In addition, the toad MMP20 gene was transcribed only in the upper jaw, presumably in teeth. These results suggest that MMP20 in a common ancestor of tetrapods might have been recruited for the processing of AMEL and conserved over 350 million years of evolution.