What is Ab42 and Ab40?
The only difference between Ab42 and Ab40 is the two additional C-terminal residues on Ab42. The concentration of Ab40 in cerebral spinal fluid has been found to be several- fold more than that of Ab42. However, Ab42 is the major component of amyloid plaques in AD brains (Miller et al.
What is the amyloidogenic pathway?
The amyloidogenic pathway is the process of Aβ biogenesis: APP is firstly cleaved by β-secretase, producing soluble β-APP fragments (sAPPβ) and C-terminal β fragment (CTFβ, C99), and C99 is further cleaved by γ-secretase, generating APP intracellular domain (AICD) and Aβ.
What is the amyloid beta 42 40 Ratio?
Beta amyloid 40 is the most common variant of beta amyloid in CSF, while beta amyloid 42 predominates in senile plaques. Decreased ratio of Beta amyloid 42/40 is a strong marker of Alzheimer’s disease and can be detected early in the disease progression, even before clinical dementia occurs.
Where is tau protein from?
The tau protein is predominantly found in brain cells (neurons). Among tau’s multiple functions in healthy brain cells, a very important one is stabilization of the internal microtubules. Tau is a small protein with a short name but a large reputation because of its association with multiple brain diseases.
What causes the amyloidogenic pathway?
The amyloidogenic pathway starts with β-secretase cleavage by BACE1 on the N-terminal part of the Aβ domain (Sinha et al., 1999; Vassar et al., 1999), releasing sAPPβ from a membrane-anchored fragment named βCTF or C99, which is subsequently cleaved by γ-secretase to release Aβ in the intraluminal space and AICD in the …
How can you detect neurofibrillary tangles?
Detection of neurofibrillary tangles can employ traditional histological or histofluorescent staining methods (e.g., Bielschowsky silver stain or thioflavin-S) or more recently immunohistochemical techniques using antibodies against tau as shown in Fig.