Presenilin-2 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
that (in humans) is encoded by the ''PSEN2''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Function
Alzheimer's disease (AD) patients with an inherited form of the disease carry mutations in the
presenilin proteins (
PSEN1; PSEN2) or the
amyloid precursor protein (APP). These disease-linked mutations result in increased production of the longer form of
amyloid-beta
Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid precursor protein (APP), which i ...
(main component of
amyloid
Amyloids are aggregates of proteins characterised by a fibrillar morphology of 7–13 nm in diameter, a beta sheet (β-sheet) secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the hu ...
deposits found in AD brains). Presenilins are postulated to regulate APP processing through their effects on
gamma-secretase, an enzyme that cleaves APP. Also, it is thought that the presenilins are involved in the cleavage of the
Notch receptor, such that they either directly regulate gamma-secretase activity or themselves are
protease
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the form ...
enzymes. Two alternative transcripts of PSEN2 have been identified.
In melanocytic cells PSEN2 gene expression may be regulated by
MITF
Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the ''MITF'' gene.
MITF is a basic helix-loop-helix leucine zipper transcription factor ...
.
Interactions
PSEN2 has been shown to
interact with:
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BCL2-like 1,
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CAPN1,
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CIB1,
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Calsenilin,
*
FHL2,
*
FLNB,
*
KCNIP4,
*
Nicastrin,
and
*
UBQLN1
Ubiquilin-1 is a protein that in humans is encoded by the ''UBQLN1'' gene.
Ubiquilins contain two domains, an N-terminal ubiquitin-like domain and a C-terminal ubiquitin-associated domain. They physically associate with both proteasomes and ubi ...
.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Early-Onset Familial Alzheimer Disease
{{gene-1-stub
Alzheimer's disease