Abstract:
:Intestinal epithelial cells (IECs) exist in a metabolic state of low oxygen tension termed "physiologic hypoxia." An important factor in maintaining intestinal homeostasis is the transcription factor hypoxia-inducible factor (HIF), which is stabilized under hypoxic conditions and mediates IEC homeostatic responses to low oxygen tension. To identify HIF transcriptional targets in IEC, chromatin immunoprecipitation (ChIP) was performed in Caco-2 IECs using HIF-1α- or HIF-2α-specific antibodies. ChIP-enriched DNA was hybridized to a custom promoter microarray (termed ChIP-chip). This unbiased approach identified autophagy as a major HIF-1-targeted pathway in IEC. Binding of HIF-1 to the ATG9A promoter, the only transmembrane component within the autophagy pathway, was particularly enriched by exposure of IEC to hypoxia. Validation of this ChIP-chip revealed prominent induction of ATG9A, and luciferase promoter assays identified a functional hypoxia response element upstream of the TSS. Hypoxia-mediated induction of ATG9A was lost in cells lacking HIF-1. Strikingly, we found that lentiviral-mediated knockdown (KD) of ATG9A in IECs prevents epithelial barrier formation by >95% and results in significant mislocalization of multiple tight junction (TJ) proteins. Extensions of these findings showed that ATG9A KD cells have intrinsic abnormalities in the actin cytoskeleton, including mislocalization of the TJ binding protein vasodilator-stimulated phosphoprotein. These results implicate ATG9A as essential for multiple steps of epithelial TJ biogenesis and actin cytoskeletal regulation. Our findings have novel applicability for disorders that involve a compromised epithelial barrier and suggest that targeting ATG9A may be a rational strategy for future therapeutic intervention.
journal_name
Mol Biol Celljournal_title
Molecular biology of the cellauthors
Dowdell AS,Cartwright IM,Goldberg MS,Kostelecky R,Ross T,Welch N,Glover LE,Colgan SPdoi
10.1091/mbc.E20-05-0291subject
Has Abstractpub_date
2020-09-15 00:00:00pages
2249-2258issue
20eissn
1059-1524issn
1939-4586journal_volume
31pub_type
杂志文章abstract::Two widely used hepatoma cell lines, mouse BW1J and human HepG2, express gene products characteristic of fetal hepatocytes, including serum albumin, whereas reporter genes driven by the albumin promoter are expressed at very low levels compared with highly differentiated hepatoma cells. We have investigated the low al...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.4.1.59
更新日期:1993-01-01 00:00:00
abstract::We recently determined the nucleotide sequence of the gene encoding p28, a light chain of inner dynein arms of Chlamydomonas axonemes. Here, we show that p28 is the protein encoded by the IDA4 locus. p28, and the dynein heavy chains normally associated with it, are completely absent from the flagella and cell bodies o...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.6.6.713
更新日期:1995-06-01 00:00:00
abstract::Proper functioning of the protein-folding quality control network depends on the network's ability to discern diverse structural perturbations to the native states of its protein substrates. Despite the centrality of the detection of misfolded states to cell home-ostasis, very little is known about the exact sequence ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E11-05-0463
更新日期:2011-12-01 00:00:00
abstract::The intracellular trafficking of the epidermal growth factor receptor (EGFR) is regulated by a cross-talk between calmodulin (CaM) and protein kinase Cdelta (PKCdelta). On inhibition of CaM, PKCdelta promotes the formation of enlarged early endosomes and blocks EGFR recycling and degradation. Here, we show that PKCdel...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e07-05-0411
更新日期:2008-01-01 00:00:00
abstract::We have previously identified a novel family of proteins called the GGAs (Golgi-localized, gamma-ear-containing, ADP-ribosylation factor-binding proteins). These proteins consist of an NH(2)-terminal VHS domain, followed by a GAT domain, a variable domain, and a gamma-adaptin ear homology domain. Studies from our own ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.12.11.3573
更新日期:2001-11-01 00:00:00
abstract::Cdc25, the dual-specificity phosphatase that dephosphorylates the Cdc2-cyclin B complex at mitosis, is highly regulated during the cell cycle. In Xenopus egg extracts, Cdc25 is associated with two isoforms of the 14-3-3 protein. Cdc25 is complexed primarily with 14-3-3epsilon and to a lesser extent with 14-3-3zeta. Th...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.9.2.345
更新日期:1998-02-01 00:00:00
abstract::A cornerstone of the antiviral interferon response is phosphorylation of eukaryotic initiation factor (eIF)2alpha. This limits the availability of eIF2.GTP.Met-tRNA(i)(Met) ternary complexes, reduces formation of 43S preinitiation complexes, and blocks viral (and most cellular) mRNA translation. However, many viruses ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e06-06-0478
更新日期:2006-11-01 00:00:00
abstract::Human HT2-19 cells with a conditional cdk1 mutation stop dividing upon cdk1 inactivation and undergo multiple rounds of endoreplication. We show herein that major cell cycle events remain synchronized in these endoreplicating cells. DNA replication alternates with gap phases and cell cycle-specific cyclin E expression...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e02-12-0850
更新日期:2003-09-01 00:00:00
abstract::The assembly of four soluble N-ethylmaleimide-sensitive factor attachment protein receptor domains into a complex is essential for membrane fusion. In most cases, the four SNARE-domains are encoded by separate membrane-targeted proteins. However, in the exocytotic pathway, two SNARE-domains are present in one protein,...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e07-12-1218
更新日期:2008-09-01 00:00:00
abstract::The gamma-tubulin ring complex (gammaTuRC), consisting of multiple protein subunits, can nucleate microtubule assembly. Although many subunits of the gammaTuRC have been identified, a complete set remains to be defined in any organism. In addition, how the subunits interact with each other to assemble into gammaTuRC r...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e02-01-0034
更新日期:2003-03-01 00:00:00
abstract::During oogenesis, two successive meiotic cell divisions occur without functional centrosomes because of the inactivation and subsequent elimination of maternal centrosomes during the diplotene stage of meiosis I. Despite being a conserved phenomenon in most metazoans, the means by which this centrosome behavior is con...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E15-10-0713
更新日期:2016-03-01 00:00:00
abstract::Polypeptides targeted to the yeast endoplasmic reticulum (ER) posttranslationally are thought to be kept in the cytoplasm in an unfolded state by Hsp70 chaperones before translocation. We show here that Escherichia coli beta-lactamase associated with Hsp70, but adopted a native-like conformation before translocation i...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.9.4.817
更新日期:1998-04-01 00:00:00
abstract::Damaged DNA-binding protein 2 (DDB2), a nuclear protein, participates in both nucleotide excision repair and mRNA transcription. The transcriptional regulatory function of DDB2 is significant in colon cancer, as it regulates metastasis. To characterize the mechanism by which DDB2 participates in transcription, we inve...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E16-08-0573
更新日期:2017-01-01 00:00:00
abstract::The AP-1 transcription factor JunD is highly expressed in intestinal epithelial cells, but its exact role in maintaining the integrity of intestinal epithelial barrier remains unknown. The tight junction (TJ) protein zonula occludens (ZO)-1 links the intracellular domain of TJ-transmembrane proteins occludin, claudins...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e08-02-0175
更新日期:2008-09-01 00:00:00
abstract::Doing scientific research can be a challenging, but creative and rewarding career. However, the challenge of doing research is orders of magnitude more difficult for scientists lacking access to the necessary resources. Resource-scarce environments are quite common worldwide and are highly contingent on the financial ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E17-11-0645
更新日期:2018-06-01 00:00:00
abstract::Cytochrome c release from mitochondria promotes apoptosome formation and caspase activation. The question as to whether mitochondrial permeabilization kills cells via a caspase-independent pathway when caspase activation is prevented is still open. Here we report that proneural cells of embryonic origin, when induced ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e07-09-0858
更新日期:2008-08-01 00:00:00
abstract::The small GTPase Rac cycles between the membrane and the cytosol as it is activated by nucleotide exchange factors (GEFs) and inactivated by GTPase-activating proteins (GAPs). Solubility in the cytosol is conferred by binding of Rac to guanine-nucleotide dissociation inhibitors (GDIs). To analyze the in vivo dynamics ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e06-01-0005
更新日期:2006-06-01 00:00:00
abstract::The formation and disruption of synaptic connections during development are a fundamental step in neural circuit formation. Subneuronal structures such as neurites are known to be sensitive to the level of spontaneous neuronal activity, but the specifics of how neurotransmitter-induced calcium activity regulates neuri...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E19-09-0536
更新日期:2020-03-19 00:00:00
abstract::The PDZ domain-containing protein CAL mediates lysosomal trafficking and degradation of CFTR. Here we demonstrate the involvement of a CAL-binding SNARE protein syntaxin 6 (STX6) in this process. Overexpression of STX6, which colocalizes and coimmunoprecipitates with CAL, dramatically reduces the steady-state level an...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e09-03-0229
更新日期:2010-04-01 00:00:00
abstract::The TOR kinases are conserved negative regulators of autophagy in response to nutrient conditions, but the signaling mechanisms are poorly understood. Here we describe a complex containing the protein kinase Atg1 and the phosphoprotein Atg13 that functions as a critical component of this regulation in Drosophila. We s...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e08-12-1250
更新日期:2009-04-01 00:00:00
abstract::In this study, we examined the subcellular distribution and functions of LIMK1 in developing neurons. Confocal microscopy, subcellular fractionation, and expression of several epitope-tagged LIMK1 constructs revealed that LIMK1 is enriched in the Golgi apparatus and growth cones, with the LIM domain required for Golgi...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e03-05-0328
更新日期:2004-07-01 00:00:00
abstract::The retinoblastoma (RB) transcriptional corepressor and related family of pocket proteins play central roles in cell cycle control and development, and the regulatory networks governed by these factors are frequently inactivated during tumorigenesis. During normal growth, these proteins are subject to tight control th...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E10-06-0520
更新日期:2010-11-15 00:00:00
abstract::Membrane trafficking during cytokinesis is essential for the delivery of membrane lipids and cargoes to the division site. However, the molecular mechanisms are still incompletely understood. In this study, we demonstrate the importance of uncharacterized fission yeast proteins Mso1 and Sec1 in membrane trafficking du...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E20-01-0067
更新日期:2020-07-15 00:00:00
abstract::In pancreatic β-cells, glutamate dehydrogenase (GDH) modulates insulin secretion, although its function regarding specific secretagogues is unclear. This study investigated the role of GDH using a β-cell-specific GDH knockout mouse model, called βGlud1(-/-). The absence of GDH in islets isolated from βGlud1(-/-) mice ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E11-08-0676
更新日期:2012-10-01 00:00:00
abstract::To further elucidate the functions of actin in budding yeast and to relate actin structure to specific roles and interactions in vivo, we determined the phenotypes caused by 13 charged-to-alanine mutations isolated previously in the single Saccharomyces cerevisiae actin gene. Defects in actin organization, morphogenes...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.4.12.1277
更新日期:1993-12-01 00:00:00
abstract::Shiga-toxin-producing Escherichia coli remain a food-borne health threat. Shiga toxin is endocytosed by intestinal epithelial cells and transported retrogradely through the secretory pathway. It is ultimately translocated to the cytosol where it inhibits protein translation. We found that Shiga toxin transport through...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.e09-02-0155
更新日期:2009-10-01 00:00:00
abstract::We report here that Trypanosoma cruzi, the etiologic agent of Chagas disease, possesses two unique paralogues of the mitochondrial calcium uniporter complex TcMCU subunit that we named TcMCUc and TcMCUd. The predicted structure of the proteins indicates that, as predicted for the TcMCU and TcMCUb paralogues, they are ...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.E19-03-0152
更新日期:2019-07-01 00:00:00
abstract::When demembranated sperm nuclei are placed in a Xenopus egg extract, they become surrounded by a nuclear envelope and then swell to form morphologically typical pronuclei. Granules ranging from < 1.0 to approximately 3.0 microns in diameter appear within such nuclei. Bell et al. identified four nucleolar proteins in t...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.5.6.633
更新日期:1994-06-01 00:00:00
abstract::The putative role of sorting early endosomes (EEs) in synaptic-like microvesicle (SLMV) formation in the neuroendocrine PC12 cell line was investigated by quantitative immunoelectron microscopy. By BSA-gold internalization kinetics, four distinct endosomal subcompartments were distinguished: primary endocytic vesicles...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.10.12.4163
更新日期:1999-12-01 00:00:00
abstract::We applied a combination of laser microsurgery and quantitative polarization microscopy to study kinetochore-independent forces that act on chromosome arms during meiosis in crane fly spermatocytes. When chromosome arms located within one of the half-spindles during prometa- or metaphase were cut with the laser, the a...
journal_title:Molecular biology of the cell
pub_type: 杂志文章
doi:10.1091/mbc.12.12.4054
更新日期:2001-12-01 00:00:00