B2.025 Prework 3 Alzheimer's Disease Flashcards
what is APP?
amyloid precursor protein
what type of protein is APP?
membrane spanning
how many proteolytic sites are found on APP?
3; beta, alpha, gamme
what is the function of the full length APP?
unknown
what is the function of the APP cleaved at the alpha site?
growth factor
what two enzymes create the AB from APP?
beta and gamma secretase
what is the C-terminus portion of APP cleaved from the gamma site called?
AICD
what is the fragment of APP cleaved only at the beta site called?
C99
what is the structural model of c99?
parts are integral, but other regions are intrinsically disordered
very flexible in nature
is the creation of AB peptides always toxic?
no, single peptides are normal
oligomers are toxic and are degraded by cell
when oligomers aren’t degraded they can aggregate into toxic AB sheets
what is a current hypothesis about why AB oligomers are toxic?
may form pores in membranes
what is the function of tau in the normal brain?
promotes microtubule assembly and maintains sturcture
what is the difference between tau in a normal brain vs an Alzheimer’s brain?
4-8x physiologic hyperphosphorylated tau
does not bind/stabilize microtubules
forms tau tangles
what structural class is tau in?
intrinsically disordered; takes up a much larger volume than a globular protein
