Jiankang Zhang, Jinxiao Chen, Da Wo, En Ma, Hongwei Yan, Jun Peng, Dan-Ni Ren, Weidong Zhu
{"title":"Physical and functional interactions between LDLR family members and CXCR4 in breast cancer.","authors":"Jiankang Zhang, Jinxiao Chen, Da Wo, En Ma, Hongwei Yan, Jun Peng, Dan-Ni Ren, Weidong Zhu","doi":"10.1111/febs.70016","DOIUrl":"https://doi.org/10.1111/febs.70016","url":null,"abstract":"<p><p>C-X-C chemokine receptor type 4 (CXCR4) belongs to the seven-span G protein-coupled receptor family and plays an important role in promoting cancer metastasis. The single-span receptor, low-density lipoprotein receptor-related protein 6 (LRP6) is commonly considered to be a co-receptor of Wnt and plays an indispensable role during animal development. We recently demonstrated that LRP6 directly binds to CXCR4 via its ectodomain and prevents CXCR4-induced breast cancer metastasis. As a result of structural similarity, LRP6 is also categorized within the low-density lipoprotein receptor (LDLR) family that is involved in lipoprotein transport. We therefore explored whether other LDLR family members could interact with CXCR4. Immunoprecipitation and western blotting analysis showed that LDLR and very low-density lipoprotein receptor (VLDLR) physically interacted with CXCR4. Although stromal cell-derived factor 1/CXCR4 signaling was inhibited by LDLR and LRP1, it was promoted by VLDLR, LRP8 and apolipoprotein E, a general agonist of the LDLR family. Furthermore, breast cancer patients with high CXCR4 expression exhibited the worst prognosis only when combined with high levels of VLDLR/LRP8/apolipoprotein E or low expression of LDLR/LRP1, further suggesting distinct positive and negative roles of LDLR family members in regulating CXCR4. Additional members of the LDLR family, SORL1 and LRP2, also showed a negative correlation with CXCR4 in the prognosis of breast cancer patients. The findings of the present study show that the LDLR family can regulate CXCR4, endowing its members with a previously undescribed role, also suggesting their potential as new breast cancer therapeutic targets and prognostic markers.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hidde R Zuidhof, Christine Müller, Gertrud Kortman, René Wardenaar, Ekaterina Stepanova, Fabricio Loayza-Puch, Cornelis F Calkhoven
{"title":"The m6A demethylase FTO promotes C/EBPβ-LIP translation to perform oncogenic functions in breast cancer cells.","authors":"Hidde R Zuidhof, Christine Müller, Gertrud Kortman, René Wardenaar, Ekaterina Stepanova, Fabricio Loayza-Puch, Cornelis F Calkhoven","doi":"10.1111/febs.70033","DOIUrl":"https://doi.org/10.1111/febs.70033","url":null,"abstract":"<p><p>N6-methyladenosine (m6A) is a prevalent posttranscriptional mRNA modification involved in the regulation of transcript turnover, translation, and other aspects of RNA fate. The modification is mediated by multicomponent methyltransferase complexes (so-called writers) and is reversed through the action of the m6A-demethylases fat mass and obesity-associated (FTO) and alkB homolog 5 (ALKBH5) (so-called erasers). FTO promotes cell proliferation, colony formation and metastasis in models of triple-negative breast cancer (TNBC). However, little is known about genome-wide or specific downstream regulation by FTO. Here, we examined changes in the genome-wide transcriptome and translatome following FTO knockdown in TNBC cells. Unexpectedly, FTO knockdown had a limited effect on the translatome, while transcriptome analysis revealed that genes related to extracellular matrix (ECM) and epithelial-mesenchymal transition (EMT) are regulated through yet unidentified mechanisms. Differential translation of CEBPB mRNA into the C/EBPβ transcription factor isoform C/EBPβ-LIP is known to act in a pro-oncogenic manner in TNBC cells through regulation of EMT genes. Here we show that FTO is required for efficient C/EBPβ-LIP expression, suggesting that FTO has oncogenic functions through regulation of C/EBPβ-LIP.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Matriptase-mediated PAR2 activation drives monocyte-to-macrophage differentiation and polarization under hypoxic conditions.","authors":"Arpana Singh, Avinandan Bhoumick, Prosenjit Sen","doi":"10.1111/febs.70046","DOIUrl":"https://doi.org/10.1111/febs.70046","url":null,"abstract":"<p><p>Within the intricate landscape of the tumour microenvironment (TME), hypoxia stands out as a pivotal factor profoundly shaping immune cell dynamics. Our study delves into this dynamic interplay, uncovering a cascade of events triggered by hypoxia. We unveil the emergence of protease-activated receptor 2 (PAR2; also known as F2R-like trypsin receptor 1 [F2RL1]) expression in monocyte cell lines (THP1) and peripheral blood mononuclear cells (PBMCs), orchestrated by the active serine protease matriptase (TMPRSS2; also known as transmembrane protease serine 2). Hypoxic conditions set the stage for a dual mechanism: lactate accumulation drives extracellular pH reduction, and facilitates matriptase activation from its latent form. A 10 mm lactate threshold activates matriptase, which in turn activates PAR2, driving monocytes towards M1 macrophage differentiation through the AKT2-NF-κβ axis. This triggers miR155 expression, which suppresses cytokine signaling 1 (SOCS1), a key regulator of M1-M2 polarisation, while NF-κβ enhances proinflammatory responses. Notably, our study reveals a temporal switch in this hypoxia-driven process. After 48 h of hypoxia, lactate levels rise to 25 mm, suppressing matriptase activation and driving a shift towards M2 polarisation. This transition, marked by reduced miR155 expression via AKT2-NFκβ axis inactivation, highlights the dynamic nature of macrophage polarisation. Our findings demonstrate matriptase as a key regulator driving macrophage polarisation towards the M1 phenotype within hypoxic microenvironments. This insight into macrophage behaviour under hypoxia suggests new strategies for immune modulation to counter tumour progression.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143525680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amalie C A Skogvold, Heidi T Brakestad, Heidi Erlandsen, Ingar Leiros
{"title":"Crystal structure and biochemical analysis of the dimeric transaminase DoeD provides insights into ectoine degradation.","authors":"Amalie C A Skogvold, Heidi T Brakestad, Heidi Erlandsen, Ingar Leiros","doi":"10.1111/febs.70043","DOIUrl":"https://doi.org/10.1111/febs.70043","url":null,"abstract":"<p><p>The pyridoxal-5'-phosphate-dependent enzyme DoeD is a L-2,4-diaminobutyric acid (DABA) transaminase that is part of the degradation pathway of the compatible solute ectoine. Ectoines are used by halophilic organisms to maintain osmotic balance under fluctuating salt concentrations (osmoadaptation). Classified under class III ω-aminotransferases, DoeD utilizes substrates with terminal amines, facilitated by dual substrate recognition involving two binding pockets, the O-pocket and the P-pocket. In this study, we have determined the first crystal structure of DoeD at 1.5 Å and conducted a biochemical and biophysical characterization of the dimeric DABA transaminase from the halophilic bacterium and model organism Chromohalobacter salexigens DSM 3043. Our findings reveal that pyruvate is the preferred co-substrate and that DoeD has a broad pH tolerance, minimal salt requirements, and can utilize a variety of amino donors. The crystal structure and substrate specificity studies of this highly expressed and stable DoeD suggest opportunities for enhancing enzymatic activity through targeted mutagenesis, optimizing it for industrial applications in green chemistry for chiral amine synthesis.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143525678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yiming Yang Jónatansdóttir, Óttar Rolfsson, Jens G Hjörleifsson
{"title":"Human glycolysis isomerases are inhibited by weak metabolite modulators.","authors":"Yiming Yang Jónatansdóttir, Óttar Rolfsson, Jens G Hjörleifsson","doi":"10.1111/febs.70049","DOIUrl":"https://doi.org/10.1111/febs.70049","url":null,"abstract":"<p><p>Modulation of enzyme activity by metabolites represents the most efficient and rapid way of controlling metabolism. Investigating enzyme-metabolite interactions can deepen our understanding of metabolic control and aid in identifying enzyme modulators with potential therapeutic applications. These interactions vary in strength, with dissociation constants (K<sub>d</sub>) ranging from strong (nm) to weak (μm-mm). However, weak interactions are often overlooked due to the challenges in studying them. Despite this, weak modulators can reveal unknown binding modes and serve as starting points for compound optimization. In this study, we aimed to identify metabolites that weakly modulate the activity of human glucose-6-phosphate isomerase (GPI) and triosephosphate isomerase (TPI), which are potential therapeutic targets in tumor glycolysis. Through a combination of activity and binding assays, the screening revealed multiple weak inhibitors for the two targets, causing partial attenuation of their activity, with K<sub>d</sub> and K<sub>i</sub> in the low mm range. X-ray crystallography revealed six orthosteric ligands binding to the active sites - four inhibitors of GPI and two of TPI. Our findings underscore the role of weak interactions in enzyme regulation and may provide structural insights that could aid the design of inhibitors targeting human GPI and TPI in cancer intervention.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143525679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Min June Yang, Haeun Lee, Donguk Kang, Chin-Ju Park
{"title":"Biophysical investigation of the molecular interaction between minichromosome maintenance protein 6 and Bloom syndrome helicase.","authors":"Min June Yang, Haeun Lee, Donguk Kang, Chin-Ju Park","doi":"10.1111/febs.70047","DOIUrl":"https://doi.org/10.1111/febs.70047","url":null,"abstract":"<p><p>The minichromosome maintenance protein (MCM) complex and Bloom syndrome helicase (BLM) are crucial components in DNA replication and cell division. MCM, a hexameric helicase that unwinds double-stranded DNA, serves as an important diagnostic and prognostic biomarker for cancer cells and a target for anticancer drug development. BLM, associated with G-quadruplex structures, is another key helicase in maintaining genomic stability. In this study, we investigate the interaction between MCM6 and BLM at the atomic level, as their expression levels are highly correlated in various cancer types, with elevated levels indicating poor prognosis. To elucidate the molecular basis of MCM6/BLM interaction, we employed fluorescence polarization anisotropy analysis, NMR chemical shifts perturbation analysis (CSP), and paramagnetic relaxation enhancement (PRE) experiments. MCM6 binding domain (MBD) C and D exhibit similar binding affinities to MCM6 winged-helix domain (WHD). However, significant CSPs with MBD-D and PRE experiments suggested that MBD-D is closer to MCM6 WHD than MBD-C. Despite both proteins containing numerous negatively charged residues, hydrophobic interactions govern the association between MCM6 WHD and BLM MBD-D. This biophysical characterization of the MCM6/BLM interaction provides new insights into their functional relationship and challenges existing models. Our findings reveal that MCM6 binds BLM at a different site than its other known partner chromatin licensing and DNA replication factor. Understanding these protein-protein interactions at the molecular level may contribute to the development of novel anticancer therapies targeting the MCM6/BLM interaction.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andria Theodoulou, Thilo Speckmann, Louiza Potamiti, Otto Baba, Tsuyoshi Morita, Anthi Drousiotou, Mihalis I Panayiotidis, Annette Schürmann, Petros P Petrou
{"title":"Stbd1 stimulates AMPK signaling and alleviates insulin resistance in an in vitro hepatocyte model.","authors":"Andria Theodoulou, Thilo Speckmann, Louiza Potamiti, Otto Baba, Tsuyoshi Morita, Anthi Drousiotou, Mihalis I Panayiotidis, Annette Schürmann, Petros P Petrou","doi":"10.1111/febs.70040","DOIUrl":"https://doi.org/10.1111/febs.70040","url":null,"abstract":"<p><p>Starch-binding domain-containing protein 1 (Stbd1) is a glycogen-binding protein which localizes to the endoplasmic reticulum (ER) membrane and ER-mitochondria contact sites (ERMCs). The protein undergoes N-myristoylation, which is a major determinant of its subcellular targeting. Stbd1 has been implicated in the control of glucose homeostasis, as evidenced by the finding that mice with targeted inactivation of Stbd1 display insulin resistance associated with increased ERMCs in the liver. In the present study, we addressed the effects of increased Stbd1 expression levels on insulin signaling. We show that Stbd1 overexpression enhances cellular sensitivity to insulin and improves insulin resistance in an in vitro hepatocyte cell model. We further demonstrate that increased Stbd1 expression levels are associated with enhanced activation of the AMP-activated protein kinase (AMPK), which is a central regulator of metabolism and an attractive therapeutic target for metabolic disorders related to insulin resistance, such as type 2 diabetes (T2D). The activation of AMPK signaling and the improved cellular response to insulin induced by Stbd1 overexpression occurred independently of N-myristoylation and associated changes in the number of ERMCs, glycogen levels, mitochondrial calcium, mitochondrial morphology, and respiratory function. Collectively, our findings uncover a new level of interaction between Stbd1 and AMPK, with Stbd1 acting as an upstream activator of AMPK signaling. Given that first-line drug treatments for insulin resistance and T2D are known activators of the AMPK pathway, these findings may provide a new perspective for the development of more effective therapeutic strategies.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Expanding our understanding of synucleinopathies: proteinopathy, proteinopenia, and lipidopathy.","authors":"Manuel Flores-León, Tiago F Outeiro","doi":"10.1111/febs.70011","DOIUrl":"https://doi.org/10.1111/febs.70011","url":null,"abstract":"<p><p>A possible consequence of the process of protein aggregation in neurodegenerative diseases is the depletion of soluble protein species (proteinopenia), which may, at least in some cases, reduce protein function/activity. This concept, which is often overlooked, may play a role in synucleinopathies such as Parkinson's disease (PD), and dementia with Lewy bodies (DLB), where the protein α-synuclein (aSyn) is known to accumulate in insoluble inclusions. aSyn is at the crossroads between cellular proteostasis and lipidostasis networks and, therefore, we must be aware of the complexity we face when we try to understand the molecular basis of synucleinopathies. Importantly, aSyn and β-glucocerebrosidase (GCase), a sphingolipid hydrolase also strongly implicated in PD and DLB, are connected to lipid biology and to protein quality control function. Thus, changes in the normal relationship between these two proteins may shift the balance in the cell and lead to proteinopathy and/or proteinopenia, while also affecting lipidostasis of cells in the brain. Thus, pathological mechanisms that are a consequence of (a) loss-of-function, (b) gain-of-toxic function, and (c) alterations in lipidostasis need to be carefully analyzed and integrated in our study of the molecular underpinnings of neurodegenerative mechanisms. Here, we highlight implications of the depletion of the soluble form of aSyn, and of GCase, and discuss how state-of-the-art 'omics technologies' could be deployed to assist in the clinical assessment of synucleinopathies.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A naturally evolved metal ion transfer mechanism that improves the catalytic performance and stability of superoxide dismutase.","authors":"Jingjing Zhang, Jingjing Liu, Xuehua Wan, Linbo Sun, Jingbo Gong, Jiabin Li, Yijia Wang, Fang Zhao, Wei Wang","doi":"10.1111/febs.70041","DOIUrl":"https://doi.org/10.1111/febs.70041","url":null,"abstract":"<p><p>Inadequate binding of metal ions is a major cause of low activity and loss of function in metalloenzymes such as superoxide dismutase (SOD). In this study, we report a previously undescribed metal ion transfer mechanism mediated by the metal ion binding domain (MIBD) of SOD, which significantly improves SOD activity and stability. MIBD is mainly found in the N-terminal domain of SOD from Paenibacillus, which evolves under a metal ion deficient environment. MIBD can capture and transfer Fe<sup>2+</sup> to the conserved functional domain of SOD (SODA) via inter- and intramolecular interactions to maintain and enhance enzymatic activity at different ion concentrations. MIBD also exhibits a similar positive effect on the activity and stability of SOD from other species. Moreover, MIBD does not affect the optimum temperature and optimum pH of SOD, but it increases SOD activity to varying degrees compared with SODA at different temperatures and pHs. This unique MIBD also significantly improves the resistance of SOD to protein denaturants and detergents such as Gdn-HCl, Urea, and SDS, and improves physiological stability of SOD in simulated digestive fluids. This naturally evolved mechanism of SOD provides valuable insights into the design of well-performing metalloenzymes.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Human transmembrane protein 68 links triacylglycerol synthesis to membrane lipid homeostasis.","authors":"Fansi Zeng, Christoph Heier, Qing Yu, Huimin Pang, Feifei Huang, Zheng Zhao, Pingan Chang","doi":"10.1111/febs.70044","DOIUrl":"https://doi.org/10.1111/febs.70044","url":null,"abstract":"<p><p>Transmembrane protein 68 (TMEM68) is a recently identified mammalian triacylglycerol (TAG) synthase with high expression in the brain. How TMEM68 regulates cellular lipid metabolism in concert with other enzymatic pathways remains poorly understood. In this study, we assessed TMEM68 function in neuro- and glioblastoma cells by combining genetic gain- and loss-of-function approaches with lipidomics. We found that TMEM68 promotes TAG synthesis and lipid droplet formation independently of canonical acyl-CoA:diacylglycerol acyltransferase (DGAT) 1 and 2 enzymes and contributes a discrete fraction of basal cellular TAG storage. Notably, TMEM68 overexpression increased storage lipids at the expense of membrane lipids, leading to a profound reduction of ether-linked glycerophospholipids (GPLs). Moreover, altered TMEM68 expression levels were associated with diminished prevalence of polyunsaturated GPLs. We conclude that TMEM68, besides its TAG synthesis function, acts as a multifaceted regulator of membrane lipid composition and polyunsaturated fatty acid homeostasis.</p>","PeriodicalId":94226,"journal":{"name":"The FEBS journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}