Cleavage of MAGI-1, a tight junction PDZ protein, by caspases is an important step for cell-cell detachment in apoptosis

Gregorc, U; Ivanova, Saška; Thomas, Miranda; Guccione, Ernesto; Glaunsinger, Britt A.; Javier, Ron; Türk, Vito; Banks, Lawrence; Turk, Boris

doi:10.1007/s10495-006-0579-6

Cited by 24 publications

(21 citation statements)

References 61 publications

(79 reference statements)

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“…We identified a role for MAGI-1 in modulating cell-cell contact during ventral enclosure, consistent with work in vertebrate tissue culture, where loss of MAGI-1 weakens cell-cell adhesion, leading to dismantling of cell junctions [26, 27]. Loss of C. elegans magi-1 function could similarly weaken cell junctions, thereby impairing normal coordination of cell movements during ventral enclosure.…”

Section: Discussionsupporting

confidence: 80%

“…Because forward genetic approaches do not always identify modifiers or redundant genes, we used genome-wide RNAi in a hypomorphic hmp-1 /α-catenin mutant background to uncover 55 novel regulators of cell junctions in vivo. We focused on magi-1 , a critical regulator of junctional stability in vertebrate tissue culture [26, 27]. We subsequently confirmed the genetic interaction between magi-1 and the CCC using magi-1 and hmp-2 /β-catenin mutants, providing further support for their functional interaction.…”

Section: Discussionmentioning

confidence: 91%

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A Genome-wide Functional Screen Shows MAGI-1 Is an L1CAM-Dependent Stabilizer of Apical Junctions in C. elegans

et al. 2012

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Summary Background In multicellular organisms, cell-cell junctions are involved in many aspects of tissue morphogenesis. α-catenin links the cadherin-catenin complex (CCC) to the actin cytoskeleton, stabilizing cadherin-dependent adhesions. Results To identify modulators of cadherin-based cell adhesion, we conducted a genome-wide RNAi screen in C. elegans and uncovered MAGI-1, a highly conserved protein scaffold. Loss of magi-1 function in wild-type embryos results in disorganized epithelial migration and occasional morphogenetic failure. MAGI-1 physically interacts with the putative actin regulator AFD-1/afadin; knocking down magi-1 or afd-1 function in a hypomorphic α-catenin background leads to complete morphogenetic failure and actin disorganization in the embryonic epidermis. MAGI-1 and AFD-1 localize to a unique domain in the apical junction and normal accumulation of MAGI-1 at junctions requires SAX-7/L1CAM, which can bind MAGI-1 via its C-terminus. Depletion of MAGI-1 leads to loss of spatial segregation and expansion of apical junctional domains and greater mobility of junctional proteins. Conclusions Our screen is the first genome-wide approach to identify proteins that function synergistically with the CCC during epidermal morphogenesis in a living embryo. We demonstrate novel physical interactions between MAGI-1, AFD-1/afadin and SAX-7/L1CAM, which are part of a functional interactome that includes components of the core CCC. Our results further suggest MAGI-1 helps to partition and maintain a stable, spatially ordered apical junction during morphogenesis.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 91%

A Genome-wide Functional Screen Shows MAGI-1 Is an L1CAM-Dependent Stabilizer of Apical Junctions in C. elegans

et al. 2012

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“…We assume that this is because cells with activated caspase-3 started to lose cell-cell contacts and release from the urothelium, whereas neighboring cells with inactivated caspases were passively pulled into the lumen. It is well known that the disassembling of cell-cell contacts is a consequence of metalloprotease or caspase activity, which splits cell junction proteins, and several of them have already been shown to be targets of caspase-3 (Steinhusen et al 2001;Weiske et al 2001;Bojarski et al 2004;Gregorc et al 2007). …”

Section: Discussionmentioning

confidence: 99%

Apoptosis and Desquamation of Urothelial Cells in Tissue Remodeling During Rat Postnatal Development

Erman¹,

Zupančič²,

Jezernik³

2009

J Histochem Cytochem.

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S U M M A R Y Postnatal rat urothelium was studied from day 0 to day 14, when intense cell loss as part of tissue remodeling was expected. The morphological and biochemical characteristics of urothelial cells in the tissue and released cells were investigated by light and electron microscopy, by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, by annexin V/propidium iodide assay, and by immunofluorescent detection of active caspases and tight-junction protein occludin. Intense apoptosis and massive desquamation were detected between postnatal days 7 and 10. During this period, active caspases and TUNEL-positive cells were found in the urothelium. Disassembled cell-cell junctions were detected between cells. The majority of desquamated cells expressed no apoptotic cell morphology, but were active caspase positive and TUNEL positive. Ann1/PI2 apoptotic bodies and desquamated Ann1/PI1 cells were detected in the lumen. These results indicate that apoptosis and desquamation participate in urothelial cell loss in the rat early postnatal period, indispensable for fast urothelial remodeling during development. (J Histochem Cytochem 57:721-730, 2009)

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“…The 5' terminal region of the chimaeric cDNA molecule corresponds to an antisense transcript of the Magi1 gene (membrane associated guanylate kinase inverted 1) that has not previously been described. Magi1 encodes a 1200 amino acid protein involved in the assembly of multi-protein complexes on the inner surface of the plasma membrane at regions of cell-cell contact (Hirabayashi et al, 2003;Wegmann et al, 2004;Mizuhara et al, 2005;Gregorc et al, 2007). We have termed the antisense transcriptional unit Magi1OS (Magi1 Opposite Strand).…”

Section: Resultsmentioning

confidence: 99%

Tandem B1 SINE retro-elements may provide a basis for natural antisense transcription in the Magi1 locus of the mouse (Mus musculus)

2010

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Transposable elements, which are DNA sequences that can move between different sites in genomes, comprise approximately 40% of the genome of mammals and are emerging as important contributors to biological diversity. Here we report a transcription unit lying within intron 1 of the murine Magi1 (membrane associated guanylate kinase inverted 1) gene that codes for a cell-cell junction scaffolding protein. The transcription unit, termed Magi1OS (Magi1 Opposite Strand), originates from a region with tandem B1 short interspersed nuclear elements (SINEs) and is an antisense gene to Magi1. Mag1OS transcription initiates in a proximal B1 element that shows only 4% divergence from the consensus sequence, indicating that it has been recently inserted into the mouse genome and could be replication competent. Moreover, a chimaeric transcript may result from intra-chromosomal interaction and trans-splicing of the Magi1 antisense transcript (Magi1OS) and Ghrl, which codes for the multifunctional peptide hormone ghrelin. These two genes are 20 megabases apart on chromosome 6 and are transcribed in opposite directions. We propose that the Magi1OS locus may serve as a useful model system to study exaptation and retrotransposition of B1 SINEs, as well as to examine the mechanisms of intra-chromosomal trans-splicing.

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Cleavage of MAGI-1, a tight junction PDZ protein, by caspases is an important step for cell-cell detachment in apoptosis

Cited by 24 publications

References 61 publications

A Genome-wide Functional Screen Shows MAGI-1 Is an L1CAM-Dependent Stabilizer of Apical Junctions in C. elegans

A Genome-wide Functional Screen Shows MAGI-1 Is an L1CAM-Dependent Stabilizer of Apical Junctions in C. elegans

Apoptosis and Desquamation of Urothelial Cells in Tissue Remodeling During Rat Postnatal Development

Tandem B1 SINE retro-elements may provide a basis for natural antisense transcription in the Magi1 locus of the mouse (Mus musculus)

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