Cell-type and Amyloid Precursor Protein-type Specific Inhibition of Aβ Release by Bafilomycin A1, a Selective Inhibitor of Vacuolar ATPases

Knops, Jeroen; Suomensaari, Susanna; Lee, Michael; McConlogue, Lisa; Seubert, Peter; Sinha, Sukanto

doi:10.1074/jbc.270.6.2419

Cited by 112 publications

(96 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of this material in the Golgi apparatus, and to a lesser extent in the endosomes, could indicate that these are normal sites of ␥-secretase processing. This would be consistent with numerous studies pointing to the involvement of acidic compartments in A␤ biogenesis (6,30,31,99).…”

Section: Fig 8 Effects Of Rab1b(n121i) On the Intracellular Localizsupporting

confidence: 78%

Retention of the Alzheimer's Amyloid Precursor Fragment C99 in the Endoplasmic Reticulum Prevents Formation of Amyloid β-Peptide

Maltese

Wilson

Tan³

et al. 2001

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

␥-Secretase is a membrane-associated endoprotease that catalyzes the final step in the processing of Alzheimer's ␤-amyloid precursor protein (APP), resulting in the release of amyloid ␤-peptide (A␤). The molecular identity of ␥-secretase remains in question, although recent studies have implicated the presenilins, which are membrane-spanning proteins localized predominantly in the endoplasmic reticulum (ER). Based on these observations, we have tested the hypothesis that ␥-secretase cleavage of the membrane-anchored C-terminal stump of APP (i.e. C99) occurs in the ER compartment. When recombinant C99 was expressed in 293 cells, it was localized mainly in the Golgi apparatus and gave rise to abundant amounts of A␤. Co-expression of C99 with mutant forms of presenilin-1 (PS1) found in familial Alzheimer's disease resulted in a characteristic elevation of the A␤ 42 /A␤ 40 ratio, indicating that the N-terminal exodomain of APP is not required for mutant PS1 to influence the site of ␥-secretase cleavage. Biogenesis of both A␤ 40 and A␤ 42 was almost completely eliminated when C99 was prevented from leaving the ER by addition of a di-lysine retention motif (KKQN) or by co-expression with a dominant-negative mutant of the Rab1B GTPase. These findings indicate that the ER is not a major intracellular site for ␥-secretase cleavage of C99. Thus, by inference, PS1 localized in this compartment does not appear to be active as ␥-secretase. The results suggest that presenilins may acquire the characteristics of ␥-secretase after leaving the ER, possibly by assembling with other proteins in peripheral membranes.Amyloid ␤-peptide (A␤) 1 is the major molecular component of the cerebral amyloid plaques associated with Alzheimer's disease. The cellular pathways involved in the biogenesis of A␤ have been the subject of intense investigation since the discovery that A␤ originates from intracellular endoproteolytic processing of a type I membrane-spanning glycoprotein termed amyloid precursor protein (APP) (1-4). Extensive studies have established that APP can be processed via two alternative routes, one of which yields the 4-kDa A␤, whereas the other yields a truncated non-amyloidogenic peptide (p3) (5, 6). In most cells the non-amyloidogenic pathway predominates. The first step involves the cleavage of APP within the A␤ domain by a protease termed ␣-secretase (7-9). After release of the Nterminal exodomain, the residual 83-amino acid membranespanning C-terminal fragment is further processed by another protease termed ␥-secretase to remove the cytoplasmic tail and generate p3 (6, 10). Because the latter cleavage occurs within the predicted membrane spanning region of APP (11-13), ␥-secretase is generally thought to be an intramembrane protease. In the alternative amyloidogenic pathway, APP is initially cleaved proximal to the A␤ sequence by ␤-secretase, leaving a 99-amino acid C-terminal fragment (C99) that contains the intact A␤ sequence and the cytoplasmic tail (1,14,15). Thus, when ␥-secretase cuts the latter substrate, A␤ is rel...

show abstract

Section: Fig 8 Effects Of Rab1b(n121i) On the Intracellular Localizsupporting

confidence: 78%

Retention of the Alzheimer's Amyloid Precursor Fragment C99 in the Endoplasmic Reticulum Prevents Formation of Amyloid β-Peptide

Maltese

Wilson

Tan³

et al. 2001

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…1c, lane 2). Earlier studies in intact cells documented that soluble A␤ production from the Swedish ␤APP variant is inhibited by baf A1, a proton ATPase inhibitor (21), indicating that A␤ is generated in an acidic compartment (22,23). A␤ production in the permeabilized cell system (Fig.…”

Section: Resultsmentioning

confidence: 99%

Generation of Alzheimer β-amyloid protein in the trans-Golgi network in the apparent absence of vesicle formation

Sweeney

Wang

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

263

212

View full text Add to dashboard Cite

“…Supernatants (Sup 1) were reserved for analysis; the pellets were solubilized with the above buffer containing 1% Nonidet P-40, respun as above, and the resulting supernatants (Sup 2) were also analyzed. Equivalent amounts of supernatant protein were analyzed by Western blotting using 2 g/ml of the Swedish192 antibody, which is specific for the Swedish mutant form of ␤-s-APP (22).…”

Section: Methodsmentioning

confidence: 99%

β-Secretase Processing of the β-Amyloid Precursor Protein in Transgenic Mice Is Efficient in Neurons but Inefficient in Astrocytes

Zhao

Paganini

Mucke

et al. 1996

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Alzheimer's disease is characterized by the extracellular deposition of ␤-amyloid peptide (A␤) in cerebral plaques and evidence is accumulating that amyloid is neurotoxic. A␤ is derived from the ␤-amyloid precursor protein (APP). Proteolytic processing of APP by the enzyme, ␤-secretase, produces the N terminus of A␤, and releases a secreted ectodomain of APP (␤-s-APP). To develop animal models for measuring ␤-secretase activity in specific brain cells in vivo, we have targeted the expression of the full-length human APP to either neurons or astrocytes in transgenic mice using the neuronspecific enolase (NSE) promoter or a modified glial fibrillary acidic protein (GFAP) gene, respectively. The APP cDNAs expressed were mutated (KM to NL at 670/ 671) to encode amino acid substitutions that enhance amyloidogenic processing in vitro. Western analyses revealed abundant production of ␤-s-APP in the brains of NSE-APP mice and enzyme-linked immunosorbent assay analyses showed production of A␤ in fetal primary mixed brain cultures and brain homogenates from these transgenic animals. Because the NSE promoter drives expression primarily in neurons, this provides in vivo evidence that the ␤-secretase cleavage necessary for generation of ␤-s-APP and A␤ is efficiently performed in neurons. In contrast, only little ␤-s-APP was detected in brain homogenates of GFAP-APP mice, indicating that astrocytes show very little ␤-secretase activity in vivo. This provides strong in vivo evidence that the major source of A␤ in brain is from neurons and not from astrocytes.The extracellular deposition of ␤-amyloid peptide (A␤) 1 in senile plaques is an early and invariant feature of Alzheimer's disease (AD). This 39 -43-amino acid peptide is the major component of plaques and is proteolytically processed from the ␤-amyloid precursor protein (APP) (1, 2). APP is expressed in all tissues, and the relative amount of A␤ processed from APP varies in different cell types in culture (3-5). The cellular source of A␤ deposited into plaques in the brain is unknown. Mutations in APP are responsible for some forms of familial AD, supporting the hypothesis that APP and A␤ are central to the disease process (6). Missense mutations immediately Nterminal to the A␤ region of APP 2 lead to a 5-10-fold enhancement of A␤ produced from APP in vitro, strongly supporting the role of A␤ in the development of AD in this family (7,8). Other families, with mutations at the 717 position of APP, have been shown to produce increased amounts of the more amyloidogenic 42-amino acid form of A␤ from APP (9). These findings suggest that factors governing the metabolic processing of APP play a direct pathogenic role in Alzheimer's disease.The majority of APP is cleaved in the middle of the A␤ region, releasing a secreted ectodomain containing the first 16 amino acids of A␤ (␣-s-APP). This processing, mediated by an unidentified enzymatic activity termed "␣-secretase" precludes A␤ formation (10). In an alternative pathway, cleavage between Met 671 and Asp 672 by a likewise unid...

show abstract

Cell-type and Amyloid Precursor Protein-type Specific Inhibition of Aβ Release by Bafilomycin A1, a Selective Inhibitor of Vacuolar ATPases

Cited by 112 publications

References 25 publications

Retention of the Alzheimer's Amyloid Precursor Fragment C99 in the Endoplasmic Reticulum Prevents Formation of Amyloid β-Peptide

Retention of the Alzheimer's Amyloid Precursor Fragment C99 in the Endoplasmic Reticulum Prevents Formation of Amyloid β-Peptide

Generation of Alzheimer β-amyloid protein in the trans-Golgi network in the apparent absence of vesicle formation

β-Secretase Processing of the β-Amyloid Precursor Protein in Transgenic Mice Is Efficient in Neurons but Inefficient in Astrocytes

Contact Info

Product

Resources

About