Title : The novel membrane
protein TMEM59 modulates complex glycosylation, cell surface expression, and secretion of the
amyloid precursor protein
Abstract :
- Ectodomain shedding of the amyloid precursor protein ( APP ) by the two proteases alpha- and beta-secretase is a key regulatory event in the generation of the Alzheimer disease amyloid beta peptide (Abeta)
- At present, little is known about the cellular mechanisms that control APP shedding and Abeta generation
- Here, we identified a novel protein , transmembrane protein 59 ( TMEM59 ), as a new modulator of APP shedding
- TMEM59 was found to be a ubiquitously expressed, Golgi-localized protein
- TMEM59 transfection inhibited complex N- and O-glycosylation of APP in cultured cells
- Additionally, TMEM59 induced APP retention in the Golgi and inhibited Abeta generation as well as APP cleavage by alpha- and beta-secretase cleavage, which occur at the plasma membrane and in the endosomes, respectively
- Moreover, TMEM59 inhibited the complex N-glycosylation of the prion protein , suggesting a more general modulation of Golgi glycosylation reactions
- Importantly, TMEM59 did not affect the secretion of soluble proteins or the alpha-secretase like shedding of tumor necrosis factor alpha , demonstrating that TMEM59 did not disturb the general Golgi function
- The phenotype of TMEM59 transfection on APP glycosylation and shedding was similar to the one observed in cells lacking conserved oligomeric Golgi ( COG ) proteins COG1 and COG2
- Both proteins are required for normal localization and activity of Golgi glycosylation enzymes
- In summary, this study shows that TMEM59 expression modulates complex N- and O-glycosylation and suggests that TMEM59 affects APP shedding by reducing access of APP to the cellular compartments, where it is normally cleaved by alpha- and beta-secretase
Output (sent_index, trigger,
protein,
sugar,
site):
- 0. glycosylation, , amyloid precursor protein, -, -
- 5. O-glycosylation, , APP, -, -
- 7. N-glycosylation, , protein, -, -
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):