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ELife Jun 2024Transport and localization of melanosome at the periphery region of melanocyte are depended on myosin-5a (Myo5a), which associates with melanosome by interacting with...
Transport and localization of melanosome at the periphery region of melanocyte are depended on myosin-5a (Myo5a), which associates with melanosome by interacting with its adaptor protein melanophilin (Mlph). Mlph contains four functional regions, including Rab27a-binding domain, Myo5a GTD-binding motif (GTBM), Myo5a exon F-binding domain (EFBD), and actin-binding domain (ABD). The association of Myo5a with Mlph is known to be mediated by two specific interactions: the interaction between the exon-F-encoded region of Myo5a and Mlph-EFBD and that between Myo5a-GTD and Mlph-GTBM. Here, we identify a third interaction between Myo5a and Mlph, that is, the interaction between the exon-G-encoded region of Myo5a and Mlph-ABD. The exon-G/ABD interaction is independent from the exon-F/EFBD interaction and is required for the association of Myo5a with melanosome. Moreover, we demonstrate that Mlph-ABD interacts with either the exon-G or actin filament, but cannot interact with both of them simultaneously. Based on above findings, we propose a new model for the Mlph-mediated Myo5a transportation of melanosomes.
Topics: Melanosomes; Myosin Type V; Animals; Mice; Adaptor Proteins, Signal Transducing; Protein Binding; Humans; Myosin Heavy Chains; Melanocytes
PubMed: 38900147
DOI: 10.7554/eLife.93662 -
Nature Communications Jun 2024Cytokinesis is the final step of the cell division cycle that leads to the formation of two new cells. Successful cytokinesis requires significant remodelling of the...
Cytokinesis is the final step of the cell division cycle that leads to the formation of two new cells. Successful cytokinesis requires significant remodelling of the plasma membrane by spatially distinct β- and γ-actin networks. These networks are generated by the formin family of actin nucleators, DIAPH3 and DIAPH1 respectively. Here we show that β- and γ-actin perform specialized and non-redundant roles in cytokinesis and cannot substitute for one another. Expression of hybrid DIAPH1 and DIAPH3 proteins with altered actin isoform specificity relocalized cytokinetic actin isoform networks within the cell, causing cytokinetic failure. Consistent with this we show that β-actin networks, but not γ-actin networks, are required for the maintenance of non-muscle myosin II and RhoA at the cytokinetic furrow. These data suggest that independent and spatially distinct actin isoform networks form scaffolds of unique interactors that facilitate localized biochemical activities to ensure successful cell division.
Topics: rhoA GTP-Binding Protein; Cytokinesis; Formins; Actins; Humans; Myosin Type II; Adaptor Proteins, Signal Transducing; HeLa Cells; Animals; Protein Isoforms
PubMed: 38897998
DOI: 10.1038/s41467-024-49427-2 -
Arquivos Brasileiros de Cardiologia 2024
Topics: Humans; Biomarkers; Troponin; Risk Assessment; Risk Factors; Surgical Procedures, Operative; Postoperative Complications; Predictive Value of Tests
PubMed: 38896580
DOI: 10.36660/abc.20240140 -
F1000Research 2022Various stemness markers (SOX2, OCT4, and NANOG) have been studied in odontogenic cysts and tumors. However, studies on SALL4 having similar properties of stemness has...
BACKGROUND
Various stemness markers (SOX2, OCT4, and NANOG) have been studied in odontogenic cysts and tumors. However, studies on SALL4 having similar properties of stemness has not been documented. Additionally, insight into fascin as a migratory molecule is less explored. In this study, the expression of SALL4 and fascin were evaluated in ameloblastoma, adenomatoid odontogenic tumor (AOT), odontogenic keratocyst (OKC), dentigerous cyst (DC), radicular cyst (RC), and calcifying odontogenic cyst (COC).
METHODS
Semi-quantitative analysis of fascin and SALL4 immuno-positive cells was done in a total of 40 cases of ameloblastoma (11 plexiform, 12 follicular, 12 unicystic, and 5 desmoplastic) variants, 6 cases of AOT, 15 each of OKC, DC, RC and 5 of COC. Chi-square test was applied to evaluate the association between SALL4 and fascin expression in odontogenic cysts and tumors.
RESULTS
Fascin immunopositivity was observed in peripheral ameloblast-like cells, and weak or absent in stellate reticulum-like cells. A moderate to weak immune-reactivity to SALL4 was observed in the cytoplasm of ameloblastoma, epithelial cells of dentigerous and radicular cysts, having a marked inflammatory infiltrate, which is an interesting observation. COC and AOT had negative to weak expressions. No recurrence has been reported.
CONCLUSIONS
Expression of fascin in ameloblastomas elucidate their role in motility and localized invasion. Its expression in less aggressive lesions like DC, COC, AOT will incite to explore the other functional properties of fascin. SALL4 expression in the cytoplasm of odontogenic cysts and tumors may represent inactive or mutant forms which requires further validation.
Topics: Humans; Transcription Factors; Microfilament Proteins; Odontogenic Cysts; Carrier Proteins; Immunohistochemistry; Ameloblastoma; Odontogenic Tumors; Biomarkers, Tumor
PubMed: 38895097
DOI: 10.12688/f1000research.126091.3 -
Journal of Cellular and Molecular... Jun 2024Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by intense deposition of fat globules in the hepatic parenchyma that could potentially...
Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by intense deposition of fat globules in the hepatic parenchyma that could potentially progress to liver cirrhosis and hepatocellular carcinoma. Here, we evaluated a rat model to study the molecular pathogenesis of the spectrum of MASLD and to screen therapeutic agents. SHRSP5/Dmcr rats were fed a high-fat and cholesterol (HFC) diet for a period of 12 weeks and evaluated for the development of steatosis (MASLD), steatohepatitis, fibrosis and cirrhosis. A group of animals were sacrificed at the end of the 4th, 6th, 8th and 12th weeks from the beginning of the experiment, along with the control rats that received normal diet. Blood and liver samples were collected for biochemical and histopathological evaluations. Immunohistochemical staining was performed for α-SMA and Collagen Type I. Histopathological examinations demonstrated steatosis at the 4th week, steatohepatitis with progressive fibrosis at the 6th week, advanced fibrosis with bridging at the 8th week and cirrhosis at the 12th week. Biochemical markers and staining for α-SMA and Collagen Type I demonstrated the progression of steatosis to steatohepatitis, hepatic fibrosis and liver cirrhosis in a stepwise manner. Control animals fed a normal diet did not show any biochemical or histopathological alterations. The results of the present study clearly demonstrated that the HFC diet-induced model of steatosis, steatohepatitis, hepatic fibrosis and cirrhosis is a feasible, quick and appropriate animal model to study the molecular pathogenesis of the spectrum of MASLD and to screen potent therapeutic agents.
Topics: Animals; Liver Cirrhosis; Rats; Diet, High-Fat; Fatty Liver; Male; Liver; Disease Models, Animal; Collagen Type I; Actins
PubMed: 38894579
DOI: 10.1111/jcmm.18491 -
International Journal of Molecular... Jun 2024Arrhythmogenic cardiomyopathy (ACM) is an inherited myocardial disease at risk of sudden death. Genetic testing impacts greatly in ACM diagnosis, but gene-disease...
Arrhythmogenic cardiomyopathy (ACM) is an inherited myocardial disease at risk of sudden death. Genetic testing impacts greatly in ACM diagnosis, but gene-disease associations have yet to be determined for the increasing number of genes included in clinical panels. Genetic variants evaluation was undertaken for the most relevant non-desmosomal disease genes. We retrospectively studied 320 unrelated Italian ACM patients, including 243 cases with predominant right-ventricular (ARVC) and 77 cases with predominant left-ventricular (ALVC) involvement, who did not carry pathogenic/likely pathogenic (P/LP) variants in desmosome-coding genes. The aim was to assess rare genetic variants in transmembrane protein 43 (), desmin (), phospholamban (), filamin c (), cadherin 2 (), and tight junction protein 1 (), based on current adjudication guidelines and reappraisal on reported literature data. Thirty-five rare genetic variants, including 23 (64%) P/LP, were identified in 39 patients (16/243 ARVC; 23/77 ALVC): 22 , 9 , 2 , and 2 . No P/LP variants were found in and genes. Gene-based burden analysis, including P/LP variants reported in literature, showed significant enrichment for (3.79-fold), (10.31-fold), (117.8-fold) and (107-fold). A non-desmosomal rare genetic variant is found in a minority of ARVC patients but in about one third of ALVC patients; as such, clinical decision-making should be driven by genes with robust evidence. More than two thirds of non-desmosomal P/LP variants occur in FLNC.
Topics: Humans; Arrhythmogenic Right Ventricular Dysplasia; Female; Male; Adult; Middle Aged; Membrane Proteins; Cadherins; Desmosomes; Genetic Predisposition to Disease; Genetic Variation; Filamins; Retrospective Studies; Italy; Calcium-Binding Proteins; Antigens, CD
PubMed: 38892455
DOI: 10.3390/ijms25116267 -
International Journal of Molecular... Jun 2024are opportunistic bacteria, causing infections in plants, insects, animals and humans under certain conditions. The development of bacterial infection in the human body... (Review)
Review
are opportunistic bacteria, causing infections in plants, insects, animals and humans under certain conditions. The development of bacterial infection in the human body involves several stages of host-pathogen interaction, including entry into non-phagocytic cells to evade host immune cells. The facultative pathogen is capable of penetrating eukaryotic cells. These bacteria synthesize an actin-specific metalloprotease named protealysin. After transformation with a plasmid carrying the protealysin gene, noninvasive penetrate eukaryotic cells. This suggests that protealysin may play a key role in invasion. This review addresses the mechanisms underlying protealysin's involvement in bacterial invasion, highlighting the main findings as follows. Protealysin can be delivered into the eukaryotic cell by the type VI secretion system and/or by bacterial outer membrane vesicles. By cleaving actin in the host cell, protealysin can mediate the reversible actin rearrangements required for bacterial invasion. However, inactivation of the protealysin gene leads to an increase, rather than decrease, in the intensity of invasion. This indicates the presence of virulence factors among bacterial protealysin substrates. Indeed, protealysin cleaves the virulence factors, including the bacterial surface protein OmpX. OmpX increases the expression of the EGFR and β1 integrin, which are involved in invasion. It has been shown that an increase in the invasion of genetically modified may be the result of the accumulation of full-length OmpX on the bacterial surface, which is not cleaved by protealysin. Thus, the intensity of the invasion is determined by the balance between the active protealysin and its substrate OmpX.
Topics: Serratia; Humans; Bacterial Outer Membrane Proteins; Virulence Factors; Host-Pathogen Interactions; Animals; Actins; Metalloproteases
PubMed: 38892348
DOI: 10.3390/ijms25116159 -
International Journal of Molecular... May 2024Formin Homology Proteins (Formins) are a highly conserved family of cytoskeletal regulatory proteins that participate in a diverse range of cellular processes. FMNL2 is...
Formin Homology Proteins (Formins) are a highly conserved family of cytoskeletal regulatory proteins that participate in a diverse range of cellular processes. FMNL2 is a member of the Diaphanous-Related Formin sub-group, and previous reports suggest FMNL2's role in filopodia assembly, force generation at lamellipodia, subcellular trafficking, cell-cell junction assembly, and focal adhesion formation. How FMNL2 is recruited to these sites of action is not well understood. To shed light on how FMNL2 activity is partitioned between subcellular locations, we used biotin proximity labeling and proteomic analysis to identify an FMNL2 interactome. The interactome identified known and new FMNL2 interacting proteins with functions related to previously described FMNL2 activities. In addition, our interactome predicts a novel connection between FMNL2 and extracellular vesicle assembly. We show directly that FMNL2 protein is present in exosomes.
Topics: Formins; Humans; Proteomics; Exosomes; Mass Spectrometry; Protein Binding; HEK293 Cells; Protein Interaction Maps
PubMed: 38891874
DOI: 10.3390/ijms25115686 -
Cells May 2024Intracellular cargo delivery via distinct transport routes relies on vesicle carriers. A key trafficking route distributes cargo taken up by clathrin-mediated...
Intracellular cargo delivery via distinct transport routes relies on vesicle carriers. A key trafficking route distributes cargo taken up by clathrin-mediated endocytosis (CME) via early endosomes. The highly dynamic nature of the endosome network presents a challenge for its quantitative analysis, and theoretical modelling approaches can assist in elucidating the organization of the endosome trafficking system. Here, we introduce a new computational modelling approach for assessment of endosome distributions. We employed a model of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) with inherited mutations causing dilated cardiomyopathy (DCM). In this model, vesicle distribution is defective due to impaired CME-dependent signaling, resulting in plasma membrane-localized early endosomes. We recapitulated this in iPSC-CMs carrying two different mutations, TPM1-L185F and TnT-R141W (MUT), using 3D confocal imaging as well as super-resolution STED microscopy. We computed scaled distance distributions of EEA1-positive vesicles based on a spherical approximation of the cell. Employing this approach, 3D spherical modelling identified a bi-modal segregation of early endosome populations in MUT iPSC-CMs, compared to WT controls. Moreover, spherical modelling confirmed reversion of the bi-modal vesicle localization in RhoA II-treated MUT iPSC-CMs. This reflects restored, homogeneous distribution of early endosomes within MUT iPSC-CMs following rescue of CME-dependent signaling via RhoA II-dependent RhoA activation. Overall, our approach enables assessment of early endosome distribution in cell-based disease models. This new method may provide further insight into the dynamics of endosome networks in different physiological scenarios.
Topics: Humans; Induced Pluripotent Stem Cells; Endosomes; Myocytes, Cardiac; Endocytosis; Mutation; Computer Simulation; rhoA GTP-Binding Protein; Cardiomyopathies; Imaging, Three-Dimensional; Cardiomyopathy, Dilated; Models, Biological; Tropomyosin
PubMed: 38891055
DOI: 10.3390/cells13110923 -
Cells May 2024Plasma gelsolin (pGSN) overexpression in ovarian cancer (OVCA) disarms immune function, contributing to chemoresistance. The aim of this study was to investigate the...
Plasma gelsolin (pGSN) overexpression in ovarian cancer (OVCA) disarms immune function, contributing to chemoresistance. The aim of this study was to investigate the immunoregulatory effects of pGSN expression on natural killer (NK) cell function in OVCA. OVCA tissues from primary surgeries underwent immunofluorescent staining of pGSN and the activated NK cell marker natural cytotoxicity triggering receptor 1 to analyze the prognostic impact of pGSN expression and activated NK cell infiltration. The immunoregulatory effects of pGSN on NK cells were assessed using apoptosis assay, cytokine secretion, immune checkpoint-receptor expression, and phosphorylation of STAT3. In OVCA tissue analyses, activated NK cell infiltration provided survival advantages to patients. However, high pGSN expression attenuated the survival benefits of activated NK cell infiltration. In the in vitro experiment, pGSN in OVCA cells induced NK cell death through cell-to-cell contact. pGSN increased T-cell immunoglobulin and mucin-domain-containing-3 expression (TIM-3) on activated NK cells. Further, it decreased interferon-γ production in activated TIM-3+ NK cells, attenuating their anti-tumor effects. Thus, increased pGSN expression suppresses the anti-tumor functions of NK cells. The study provides insights into why immunotherapy is rarely effective in patients with OVCA and suggests novel treatment strategies.
Topics: Humans; Killer Cells, Natural; Female; Gelsolin; Carcinoma, Ovarian Epithelial; Drug Resistance, Neoplasm; Ovarian Neoplasms; Cell Line, Tumor; Middle Aged; Hepatitis A Virus Cellular Receptor 2; Apoptosis; STAT3 Transcription Factor; Interferon-gamma
PubMed: 38891037
DOI: 10.3390/cells13110905