Pancreatic β cell SERCA2 deficiency leads to impaired proinsulin processing and reduced ER to Golgi protein trafficking
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ABSTRACT:
PROVIDER: PRJNA855926 | ENA |
REPOSITORIES: ENA
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Project description:Impaired proinsulin processing is observed in both type 1 and type 2 diabetes. We have previously shown that reductions in endoplasmic reticulum (ER) calcium (Ca2+) in the pancreatic β cell arising from impaired activity of the Sarcoendoplasmic Reticulum Ca2+ ATPase (SERCA) pump are associated with increased proinsulin secretion. However, the mechanisms responsible for reduced proinsulin processing in the context of SERCA2 deficiency remain incompletely understood. To test this, we developed mice with β cell specific SERCA2 deletion (βS2KO mice) and S2KO INS1 cells. βS2KO mice exhibited age-dependent glucose intolerance and reduced glucose-stimulated insulin secretion without evidence of impaired insulin sensitivity. ER Ca2+ levels in islets from βS2KO mice were significantly reduced, while serum proinsulin/insulin (PI/I) ratios and whole pancreas PI/I content were elevated. Immunoblot analysis of βS2KO islets and S2KO INS-1 cells revealed reduced active forms of the proinsulin processing enzymes, PC1/3, PC2 and CPE. Restoration of SERCA2b via adenoviral transduction in S2KO INS1 cells was sufficient to restore PC1/3 and PC2 maturation and enzyme activity. Brefeldin A treatment in INS1 cells recapitulated the impairments in PC1/3 and PC2 maturation observed in S2KO cells, suggesting a disturbance in protein trafficking between the ER and Golgi. Consistent with this, trafficking assays were performed using a vesicular stomatitis virus G (VSVG) protein construct and revealed a significantly slower rate of VSVG movement from the ER to the Golgi in S2KO INS1 cells. Moreover, pancreas sections from βS2KO mice showed increased co-localization of proinsulin and ProPC2 in the early compartments of the secretory pathway. Taken together, these data suggest that loss of SERCA2 activity and ER Ca2+ loss in the pancreatic β cell leads to impaired proinsulin processing via reduced maturation and trafficking of proinsulin processing enzymes.
2023-10-11 | GSE207498 | GEO
Project description:Androgen receptor (AR) plays an essential role in normal prostate development and prostate cancer (PCa) progression. To understand the role of AR at the single-cell level, we performed single-cell transcriptome analysis on PCa cells stimulated with androgen and antiandrogen to reconstruct the dynamic and direct AR transcriptional network. Our work reveals that androgen stimulates the ER and Golgi stress response , promoting secreting protein trafficking, and inhibiting cell apoptosis. Moreover, we identify an ER-to-Golgi protein vesicle-mediated transport gene signature essential for maximal androgen-mediated ER-Golgi trafficking, cell proliferation, and association with PCa prognosis and progression. Notably, we show that AR collaborates with CREB3L2, XXX, to coordinately promote ER-Golgi trafficking of Golgi enzyme Mannosidase II and PCa cell survival. Finally, we show the inhibition of the ER-Golgi transport process with Brefeldin A leads to tumor regression. Our study collectively reveals the heterogeneity of PCa cell transcriptional response to androgen stimulation, demonstrates a functional role for increased ER-Golgi trafficking process, and provides a mechanism for how the process is augmented in PCa as well as the potential of targeting may provide novel treatment strategies.
2021-10-10 | GSE165562 | GEO
Project description:Compelling evidence indicates that defects in nucleocytoplasmic transport contribute to the pathogenesis of amyotrophic lateral sclerosis (ALS). In particular, hexanucleotide (G4C2) repeat expansions in C9orf72, the most common cause of genetic ALS, have a widespread impact on the transport machinery that regulates the nucleocytoplasmic distribution of proteins and RNAs, thereby affecting their functions. We have previously reported that the expression of G4C2 hexanucleotide repeats in cultured human and mouse cells caused a marked accumulation of poly(A) mRNAs in cell nuclei, suggesting that mRNA trafficking is impaired by expanded C9orf72-ALS repeats. To further characterize the process, in this work we set out to systematically identify the specific mRNAs that are altered in their nucleocytoplasmic distribution in the presence of C9orf72-ALS repeats. Results from RNAseq profiling of nuclear and cytoplasmic RNA fractions obtained from cells expressing G4C231 repeats show a significant accumulation of mRNAs in the nuclei of G4C231 cells, further suggesting that nuclear retention of mRNAs is a major effect of C9orf72 expanded repeats expression. Interestingly, pathway analysis shows that mRNAs involved in ER-to-Golgi trafficking are particularly enriched among the identified mRNAs. Most importantly, functional studies in cultured cells and Drosophila indicate that the membrane trafficking route regulated by ARFGAP1, a GTPase-activating protein that associates with Golgi, is specifically affected by expanded C9orf72 repeats, as well as by C9orf72-related dipeptide repeat proteins (C9-DPRs), pointing to ER-to-Golgi vesicle-mediated transport as a target of C9orf72 toxicity.
2023-08-21 | GSE235448 | GEO
Project description:The Golgi is the hub of the eukaryotic secretory pathway, trafficking proteins and lipids, as well as synthesizing complex sugars. Different biosynthetic reactions are associated with different compartments of its complex architecture. Although pre- and post-Golgi trafficking has been much studied, comparatively little is known about intra-Golgi organization. In this study, secretory vesicles and organelles were separated along an electrophoretic gradient at sub-Golgi resolution, presenting snapshots of the changing relative abundance of hundreds of resident and cargo proteins and glycans in transit through the ER, Golgi compartments and post-Golgi compartments. Furthermore, grouped features in migration profiles reveal the dominant intra-Golgi protein trafficking pathways, showing separate routes for cargo and different groups of resident proteins. As few structural characteristics of proteins or sequence motifs have been associated with specific regions of the Golgi stack, we also carried out a comparative analysis of the transmembrane regions of resident proteins associated with the main migratory profiles identifying the presence of charge amino acids adjacent to the transmembrane helix, exoplasmic Ser and Thr content and helix composition as likely contributors to protein sorting mechanisms.
2019-09-11 | PXD004596 | Pride
Project description:Description: These date form the basis for supplementary table 2 and supplementary figure 6 of the manuscript "Modelling glycan processing reveals Golgi-enzyme homeostasis upon trafficking defects and cellular differentiation" by P Fisher, H Spencer, J Thomas-Oates, AJ Wood, D Ungar in Cell Reports
2019-11-11 | PXD013211 | Pride
Project description:Profiling nucleo/cytoplasmic distribution of mRNAs identifies a role for the Golgi-to-ER trafficking in C9orf72 toxicity
| PRJNA986091 | ENA
Project description:Single-Cell Analysis Reveals Androgen Receptor Regulates ER-to-Golgi Trafficking with CREB3L2 To Drive Prostate Cancer Progression
| PRJNA694969 | ENA
Project description:The cumulative role of cellular organelle’s in shaping the life and function of a cell has been long acknowledged. While each organelle plays a specific role in the growth and development of T cells, numerous studies have thus far focused on targeting mitochondria, endoplasmic reticulum, or lysosome related pathways to improve anti-tumor T cell immune response. Here we highlight the tumor microenvironment (TME) mediated disruption of Golgi architecture and function, termed Golgi stress, contributes to altered redox signaling and affects cell survival. Importantly, the decreased expression if GM130, a marker of Golgi stress and indicating the disruption of Golgi architecture, was reverted upon treatment with hydrogen sulphide (H2S) donor GYY4137, or over expressing cystathionine β-synthase (Cbs), an enzyme involved in biosynthesis of endogenous H2S. Activation and expansion of tumor reactive TCR or chimeric antigen receptor bearing T cells expanded with exogenous H2S promoted stemness, antioxidant capacity and exhibited an increase effector cytokine secretion that correlated to increased protein translation. In in vivo models of melanoma and lymphoma, anti-tumor T cells conditioned ex vivo with exogenous H2S or overexpressing Cbs demonstrated superior tumor control upon ACT. Further, sorting anti- tumor T cells based on Golgi structure and abundance resulted in identification of a Golgihi subset of T cells with a unique metabolic signature, superior fitness, and enhanced anti-tumor capacity. These data suggest that H2S can be used an immunomodulatory agent to enhance the efficacy of ACT, and that the structure and function of the Golgi apparatus is an important feature of T cells that determines their anti-tumor capacity.
2024-11-20 | GSE249287 | GEO
Project description:Abnormal distribution of cellular cholesterol is associated with numerous diseases, including cardiovascular and neurodegenerative diseases. Regulated transport of cholesterol is critical for maintaining its proper distribution in the cell, yet the underlying mechanisms remain unclear. Here, we show that lipid transfer proteins, namely ORP9, OSBP, and GRAMD1s/Asters (GRAMD1a/GRAMD1b/GRAMD1c), control non-vesicular cholesterol transport at points of contact between the ER and the trans-Golgi network (TGN), thereby maintaining cellular cholesterol distribution. ORP9 localizes to the TGN via interaction between its tandem α-helices and ORP10/ORP11. ORP9 extracts PI4P from the TGN to prevent its overaccumulation and suppresses OSBP-mediated PI4P-driven cholesterol transport to the Golgi. By contrast, GRAMD1s transport excess cholesterol from the Golgi to the ER, thereby preventing its build-up. Cells lacking ORP9 exhibit accumulation of cholesterol at the Golgi, which is further enhanced by additional depletion of GRAMD1s with major accumulation in the plasma membrane. This is accompanied by chronic activation of the SREBP-2 signalling pathway. Our findings reveal the importance of regulated lipid transport at ER-Golgi contacts for maintaining cellular cholesterol distribution and homeostasis.
2023-09-24 | GSE240960 | GEO
Project description:VPS15 is known as a VPS34-associated protein that functions in intracellular trafficking and autophagy. Here the authors identify a role for VPS15 in cilopathy and ciliary phenotypes, and show that it interacts with GM130 and functions in IFT20-dependent cis-Golgi to cilium trafficking.
| EGAS00001002075 | EGA