The Golgi-Localized γ-Ear-Containing ARF-Binding (GGA) Proteins Alter Amyloid-β Precursor Protein (APP) Processing through Interaction of Their GAE Domain with the Beta-Site APP Cleaving Enzyme 1 (BACE1)

Abstract

Proteolytic processing of amyloid-β precursor protein (APP) by beta-site APP cleaving enzyme 1 (BACE1) is the initial step in the production of amyloid beta (Aβ), which accumulates in senile plaques in Alzheimer’s disease (AD). Essential for this cleavage is the transport and sorting of both proteins through endosomal/Golgi compartments. Golgi-localized γ-ear-containing ARF-binding (GGA) proteins have striking cargo-sorting functions in these pathways. Recently, GGA1 and GGA3 were shown to interact with BACE1, to be expressed in neurons, and to be decreased in AD brain, whereas little is known about GGA2. Since GGA1 impacts Aβ generation by confining APP to the Golgi and perinuclear compartments, we tested whether all GGAs modulate BACE1 and APP transport and processing. We observed decreased levels of secreted APP alpha (sAPPα), sAPPβ, and Aβ upon GGA overexpression, which could be reverted by knockdown. GGA-BACE1 co-immunoprecipitation was impaired upon GGA-GAE but not VHS domain deletion. Autoinhibition of the GGA1-VHS domain was irrelevant for BACE1 interaction. Our data suggest that all three GGAs affect APP processing via the GGA-GAE domain.

Meta‐Analysis of Publicly Available Chinese Hamster Ovary (CHO) Cell Transcriptomic Datasets for Identifying Engineering Targets to Enhance Recombinant Protein Yields

“…The GGA family genes were implicated in both PG and GG; GGA2 was downregulated in both and GGA3 upregulated in the GG. GGA depletion has been shown to have a missorting effect on mannose‐6‐phosphate receptors, cathepsin D and APP secretory inhibition, which was one of the top hits in our master gene list. In HeLa cells, it was found that overexpression of GGA's increases fragmentation and vacuolization of the trans‐Golgi network implying that these proteins have a role in maintaining Golgi integrity .…”

Randomized CRISPR-Cas Transcriptional Perturbation Screening Reveals Protective Genes against Alpha-Synuclein Toxicity

“…The yeast GGA1 protein has been implicated in binding ubiquitin, thus facilitating the sorting of cargo proteins from the trans-Golgi network to endosomal compartments (Takatsu et al, 2002; Zhdankina et al, 2001). Human GGA1 overexpression attenuates amyloidogenic processing of amyloid precursor proteins (APP) in Alzheimer’s disease and a rare inherited lipid-storage disease, Niemann-Pick type C (NPC) (Kosicek et al, 2014; von Einem et al, 2015). Finally, SIS1 , the yeast Hsp40 homolog of human DNAJ/HSP40 family proteins, was identified as αSyn suppressor via PRISM.…”

Metabolic Characterization of Intact Cells Reveals Intracellular Amyloid Beta but Not Its Precursor Protein to Reduce Mitochondrial Respiration

“…APP695 CMV(myc) is described in Kinoshita et al [30]. BACE-phCMV3(HA) is described in von Einem et al [31]. pUltra-hot is a lentiviral vector backbone for bi-cistronic expression of the gene of interest and the fluorescent reporter mCherry under the control of a human ubiquitin promoter.…”