Premium
A beta 46 is generated in the Golgi/ Trans‐Golgi network in Neuro 2a cells
Author(s) -
Zhao Guojun,
Sun Longsheng,
Tan Jianxin,
Mao Guozhang,
Cui MeiZhen,
Xu Xuemin
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a49-a
Subject(s) - brefeldin a , golgi apparatus , endosome , trypsinization , microbiology and biotechnology , lactacystin , tunicamycin , monensin , chemistry , ionomycin , endoplasmic reticulum , biology , biochemistry , proteasome inhibitor , proteasome , unfolded protein response , intracellular , trypsin , enzyme
Subcellular sites for generation of Aβ have been the subject of intensive research in understanding the pathogenesis of Alzheimer’s disease. We previously identified a long form of Aβ, Aβ46. Here we report that Aβ46 is generated in the Golgi/trans‐Golgi‐network (TGN) compartments in neruo 2a cells. Using brief centrifugation, Aβ46 was found to be co‐present with γ‐secretase components in 20,000 x g membrane fraction but not in 20,000 x g supernatant. Cell surface trypsinization demonstrates that Aβ46 is largely resistant to trypsinization. Treatment with brefeldin A (BFA) completely abolished Aβ46 generation, whereas monensin only exhibited inhibitory effect on Aβ46 generation at high concentrations, suggesting that Aβ46 is generated in the Golgi and TGN. In addition, neither 25mM NH4Cl nor 10μM lactacystin affected Aβ46 level, indicating that the majority of Aβ46 is not generated in endosomes/lysosomes, or preteasomes. Furthermore, addition of an Endoreticulum (ER) sorting signal to the C‐terminus of β‐amyloid precursor protein (APP) diminished the generation of Aβ46 and Aβ40/42, whereas retention of APP in the TGN with a TGN sorting motif did not affect the level of Aβ46 or Aβ40/42, confirming that Aβ46 is generated in the Golgi/TGN but not in the ER. Interestingly, we found that Aβ46 and Aβ40/42 were differentially affected by monensin, NH4Cl, lactacystin, and tunicamycin. While these drugs displayed no or less inhibitory effects on Aβ46 generation, they significantly blocked Aβ40/42 generation, suggesting that Aβ46 is generated at earlier stage in the secretory pathway than that of the generation of Aβ40/42. This work was supported by a grant from NIH (NS42314 to X. X) and by a grant from the American Heart Association (0355339B to M‐Z.C).