Neurotoxicity of beta-Amyloid Protein: Oligomerization, Channel Formation, and Calcium Dyshomeostasis.

Amyloid Beta-protein Precursor

A precursor to the AMYLOID BETA-PROTEIN (beta/A4). Alterations in the expression of the amyloid beta-protein precursor (ABPP) gene, located on chromosome 21, plays a role in the development of the neuropathology common to both ALZHEIMER DISEASE and DOWN SYNDROME. ABPP is associated with the extensive extracellular matrix secreted by neuronal cells. Upon cleavage, this precursor produces three proteins of varying amino acid lengths: 695, 751, and 770. The beta/A4 (695 amino acids) or beta-amyloid protein is the principal component of the extracellular amyloid in senile plaques found in ALZHEIMER DISEASE; DOWN SYNDROME and, to a limited extent, in normal aging.

Amyloid

A type of extracellularly deposited substance composed of an amyloid protein and additional components including HEPARAN SULFATE PROTEOGLYCAN; LAMININ; COLLAGEN TYPE IV; SERUM AMYLOID P-COMPONENT; and APOLIPOPROTEINS E which together form characteristic amyloid fibrils. The core of amyloid fibrils is formed by the stacking of overlapping beta-pleated sheet domains of the amyloid protein. There are many different amyloid proteins that have been found forming the core of the fibrils in vivo. However, amyloid can be formed from any protein that exposes beta-pleated strand conformations during unfolding or refolding. A common characteristic of amyloid is the ability to bind such dyes as CONGO RED and thioflavine.

Amyloid Precursor Protein Secretases

Endopeptidases that are specific for AMYLOID PROTEIN PRECURSOR. Three secretase subtypes referred to as alpha, beta, and gamma have been identified based upon the region of amyloid protein precursor they cleave.

Amyloid Beta-protein

A 4-kDa protein, 39-43 amino acids long, expressed by a gene located on chromosome 21. It is the major protein subunit of the vascular and plaque amyloid filaments in individuals with Alzheimer's disease and in aged individuals with trisomy 21 (DOWN SYNDROME). The protein is found predominantly in the nervous system, but there have been reports of its presence in non-neural tissue.

Amyloid Beta-peptides

Peptides generated from AMYLOID BETA-PEPTIDES PRECURSOR. An amyloid fibrillar form of these peptides is the major component of amyloid plaques found in individuals with Alzheimer's disease and in aged individuals with trisomy 21 (DOWN SYNDROME). The peptide is found predominantly in the nervous system, but there have been reports of its presence in non-neural tissue.