Posttranslational Modification and Plasma Membrane Localization of the Drosophila melanogaster Presenilin

Nowotny, Petra; Gorski, Sharon M.; Han, Sang Woo; Philips, Kacy; Ray, William J.; Nowotny, Volker; Jones, Christopher J.; Clark, Robert F.; Cagan, Ross L.; Goate, Alison M.

doi:10.1006/mcne.1999.0805

Cited by 35 publications

(32 citation statements)

References 48 publications

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“…SEL-12 undergoes endoproteolysis in C. elegans very similar to presenilin homologues of other species (18,57,58). As observed in other species, we found high levels of a SEL-12 CTF and only low amounts of the corresponding holoprotein.…”

Section: Discussionsupporting

confidence: 84%

“…1b). Endoproteolysis of SEL-12 is consistent with the findings that PSs from all other species analyzed, including mice (11), zebrafish (18), and Drosophila (57,58), are proteolytically processed as well. When we analyzed protein extracts derived from worms expressing the sel-12(ar131) allele (SEL-12 C60S), we surprisingly did not detect SEL-12 C-terminal fragments of similar molecular weight as observed in the wt worms.…”

Section: Aberrant Endoproteolysis Of Sel-12 C60s In C Elegans-sosupporting

confidence: 84%

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A Loss of Function Mutant of the Presenilin Homologue SEL-12 Undergoes Aberrant Endoproteolysis in Caenorhabditis elegans and Increases Aβ42 Generation in Human Cells

Okochi

Eimer

Böttcher

et al. 2000

Journal of Biological Chemistry

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The familial Alzheimer's disease-associated presenilins (PSs) occur as a dimeric complex of proteolytically generated fragments, which functionally supports endoproteolysis of Notch and the ␤-amyloid precursor protein (␤APP). A homologous gene, sel-12, has been identified in Caenorhabditis elegans. We now demonstrate that wild-type (wt) SEL-12 undergoes endoproteolytic cleavage in C. elegans similar to the PSs in human tissue. In contrast, SEL-12 C60S protein expressed from the sel-12(ar131) allele is miscleaved in C. elegans, resulting in a larger mutant N-terminal fragment. Neither SEL-12 wt nor C60S undergo endoproteolytic processing upon expression in human cells, suggesting that SEL-12 is cleaved by a C. elegans-specific endoproteolytic activity. The loss of function of sel-12 in C. elegans is not associated with a dominant negative activity in human cells, because SEL-12 C60S and the corresponding PS1 C92S mutation do not interfere with Notch1 cleavage. Moreover, both mutant variants increase the aberrant production of the highly amyloidogenic 42-amino acid version of amyloid ␤-peptide similar to familial Alzheimer's disease-associated human PS mutants. Our data therefore demonstrate that the C60S mutation in SEL-12 is associated with aberrant endoproteolysis and a loss of function in C. elegans, whereas a gain of misfunction is observed upon expression in human cells.

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Section: Discussionsupporting

confidence: 84%

Section: Aberrant Endoproteolysis Of Sel-12 C60s In C Elegans-sosupporting

confidence: 84%

A Loss of Function Mutant of the Presenilin Homologue SEL-12 Undergoes Aberrant Endoproteolysis in Caenorhabditis elegans and Increases Aβ42 Generation in Human Cells

Okochi

Eimer

Böttcher

et al. 2000

Journal of Biological Chemistry

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“…g-Secretase is thought to be an internal protease that cleaves within the membrane-spanning domain of all its substrate proteins. g-Secretase (PS1/NTF) is localized at the plasma membrane in cells with extensive cell-cell contacts (36)(37)(38)(39)(40)(41). On the basis of this g-secretase distribution, it did not seem that g-secretase would naturally favor Notch over E-cadherin cleavage in the well-formed spheroids.…”

Section: Discussionmentioning

confidence: 99%

Early to Intermediate Steps of Tumor Embolic Formation Involve Specific Proteolytic Processing of E-Cadherin Regulated by Rab7

Yin

Gao

Tian

et al. 2012

Molecular Cancer Research

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The lymphovascular embolus is an enigmatic entity adept at metastatic dissemination and chemotherapy resistance. Using MARY-X, a human breast cancer xenograft that exhibits florid lymphovascular emboli in mice and spheroids in vitro, we established a model where the in vitro transition stages from minced tumoral aggregates to well-formed spheroids served as a surrogate for in vivo emboli formation. MARY-X well-formed spheroids and emboli exhibited strong similarity of expression. The aggregate-to-spheroid transition stages were characterized by increased ExoC5, decreased Hgs and Rab7, increased calpains, increased full-length E-cadherin (E-cad/FL), and the transient appearance of E-cad/NTF2, a 95 kDa E-cadherin fragment and increased Notch3icd (N3icd), the latter two fragments produced by increased g-secretase. Both transient and permanent knockdowns of Rab7 in MCF-7 cells increased protein but not transcription of E-cad/FL and resulted in the de novo appearance of E-cad/NTF2, the presence of nuclear E-cad/CTF2, and increased Notch1icd (N1icd). Overexpression of Rab7 conversely decreased E-cad/FL, g-secretase (PS1/NTF), and E-cad/NTF2. Overexpression of calpains did not alter PS1/NTF but decreased E-cad/FL and E-cad/NTF2 and increased N1icd. Well-formed spheroids showed increased Rab7, absent E-cad/NTF2, decreased PS1/NTF, increased E-cad/NTF1, and increased N3icd, the latter two fragments being the direct and indirect consequences, respectively, of increased calpains (calpain 1 and calpain 2). Inhibition of calpains decreased E-cad/NTF1 but increased E-cad/NTF2 showing that calpains compete with g-secretase (PS1) for closely located cleavage/binding sites on E-cadherin and that increased calpains can shuttle even decreased

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“…These data suggest that the intracellular trafficking of Aph-1 is strictly controlled. However, the subcellular localization and trafficking of Psn complex components in Drosophila cells have not been extensively examined, although the targeting of Psn to the plasma membrane was reported (48,49). To determine the subcellular localization of the Psn complex as well as the effect of certain mutations of the conserved glycines on the subcellular localization of Aph-1, we separated the membrane fractions of ANPen cells by discontinuous iodixanol gradients (Fig.…”

Section: Certain Mutations Of the Conserved Glycines Of Aph-1 Abolishmentioning

confidence: 99%

Aph-1 Contributes to the Stabilization and Trafficking of the γ-Secretase Complex through Mechanisms Involving Intermolecular and Intramolecular Interactions

Niimura

Isoo

Takasugi

et al. 2005

Journal of Biological Chemistry

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␥-Secretase cleaves type I transmembrane proteins, including ␤-amyloid precursor protein and Notch, and requires the formation of a protein complex comprised of presenilin, nicastrin, Aph-1, and Pen-2 for its activity. Aph-1 is implicated in the stabilization of this complex, although its precise mechanistic role remains unknown. Substitution of the first glycine within the transmembrane GXXXG motif of Aph-1 causes a loss-of-function phenotype in Caenorhabditis elegans. Here, using an untranslated region-targeted RNA interference/rescue strategy in Drosophila Schneider 2 cells, we show that Aph-1 contributes to the assembly of the ␥-secretase complex by multiple mechanisms involving intermolecular and intramolecular interactions depending on or independent of the conserved glycines. Aph-1 binds to nicastrin forming an early subcomplex independent of the conserved glycines within the endoplasmic reticulum. Certain mutations in the conserved GXXXG motif affect the interaction of the Aph-1⅐nicastrin subcomplex with presenilin that mediates trafficking of the presenilin⅐Aph-1⅐nicas-trin tripartite complex to the Golgi. The same mutations decrease the stability of Aph-1 polypeptides themselves, possibly by affecting intramolecular associations through the transmembrane domains. Our data suggest that the proper assembly of the Aph-1⅐nicastrin subcomplex with presenilin is the prerequisite for the trafficking as well as the enzymatic activity of the ␥-secretase complex and that Aph-1 functions as a stabilizing scaffold in the assembly of this complex. Mutations in presenilin (PS)1 genes account for the majority of early onset familial Alzheimer's disease cases, causing an overproduction of those amyloid ␤ peptides (A␤) ending at position 42 (A␤42) that most readily form amyloid deposits (1). A␤ is derived from the ␤-amyloid precursor protein (␤APP) through sequential cleavages by ␤-and ␥-secretases (2). Genetic and biochemical studies suggest that PS is essential for the ␥-secretase-mediated intramembrane cleavage of ␤APP. Additional type 1 transmembrane proteins (e.g. notch, ErbB4, and CD44) also are cleaved by ␥-secretase to release intracellular domains that harbor biological activities (3). These data suggest that PS-dependent ␥-cleavage is involved in a novel mode of intramembrane proteolysis-dependent signal transduction.PS is a highly conserved, polytopic integral membrane protein that spans the membrane eight times and undergoes endoproteolysis to generate amino-and carboxyl-terminal fragments (reviewed in Ref. 4). The endoproteolytic fragments of PS form a heterodimer and are then incorporated into a highly stabilized, high molecular weight (HMW) protein complex, whereas the PS holoprotein forms a low molecular weight complex and is rapidly degraded (5, 6). We have shown by a systematic mutational analysis that the stabilization and HMW complex formation of PS are required for ␥-secretase activity, which is mediated by the carboxyl terminus of PS (7-9). PS carries two highly conserved intramembrane aspartates ...

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Posttranslational Modification and Plasma Membrane Localization of the Drosophila melanogaster Presenilin

Cited by 35 publications

References 48 publications

A Loss of Function Mutant of the Presenilin Homologue SEL-12 Undergoes Aberrant Endoproteolysis in Caenorhabditis elegans and Increases Aβ42 Generation in Human Cells

A Loss of Function Mutant of the Presenilin Homologue SEL-12 Undergoes Aberrant Endoproteolysis in Caenorhabditis elegans and Increases Aβ42 Generation in Human Cells

Early to Intermediate Steps of Tumor Embolic Formation Involve Specific Proteolytic Processing of E-Cadherin Regulated by Rab7

Aph-1 Contributes to the Stabilization and Trafficking of the γ-Secretase Complex through Mechanisms Involving Intermolecular and Intramolecular Interactions

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