amyloid precursor protein

amyloid precursor protein

n. Abbr. APP

A protein found in cell membranes that forms beta-amyloid fragments when cleaved by the secretase designated beta.

amyloid precursor protein (APP)

a large transmembrane glycoprotein expressed on the cell surface and of uncertain function; it may be cleaved on the cell surface to a soluble form. Alternatively, cleavage may follow endocytosis and in some cases then yields 40 to 43 abnormal amino acid peptides, which aggregate to form Ab amyloid, associated with Alzheimer's disease.

amyloid precursor protein

Abbreviation: APP

An integral membrane protein concentrated at neuron synapses that is cleaved biochemically into components, one of which is the Alzheimer's disease–associated beta amyloid. Mutations in the gene for APP on chromosome 21 account for less than 5% of early-onset familial Alzheimer's disease.

See also: protein

amyloid precursor protein

A natural brain protein that is coded for on chromosome 21. This protein is related in some way to memory. Point mutations are found in the gene for this protein in people who suffer from a familial form of early-onset ALZHEIMER'S DISEASE. Only a small proportion of cases of Alzheimer's disease, however, are caused in this way. Abnormally folded AMYLOID protein in the form of plaques and tangles occur in brain cells in Alzheimer's disease but also in chronic suppurative states in other parts of the body.