Preseniline
| Presenilin-1 | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 467 amino acids | |
| Secondary to quaternary structure | Homodimer, multipass membrane protein | |
| Isoforms | I-467, I-464, I-374, Minilin and two more | |
| Identifier | ||
| Gene name | PSEN1 | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 3.4.23.- , Aspartylpeptidase | |
| MEROPS | A22.001 | |
| Occurrence | ||
| Homology family | Presenilin | |
| Parent taxon | Chordates | |
| Presenilin-2 | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 448 amino acids | |
| Secondary to quaternary structure | Homodimer, multipass membrane protein | |
| Isoforms | 2 | |
| Identifier | ||
| Gene name | PSEN2 | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 3.4.23.- , Aspartylpeptidase | |
| MEROPS | A22.002 | |
| Occurrence | ||
| Homology family | Presenilin | |
| Parent taxon | Chordates | |
Presenilins are a family of transmembrane proteins which, together with nicastrin, PEN-2 and APH-1, form the gamma-secretase complex. Vertebrates have two presenilin genes: PSEN1 (in humans on chromosome 14 ), which contains the genetic information for presenilin 1 (PS-1) and PSEN2 (on chromosome 1 in humans) for presenilin 2 (PS-2). Both genes are conserved between species ; there is little difference between the rat gene and that of humans. The roundworm Caenorhabditis elegans also has two genes, sel-12 and hop-1 called, which are similar to the presenilines and probably have the same function.
Presenilins are split into a larger N-terminal and a smaller C-terminal piece in the alpha-helical region of one of the cytoplasmic loops. Both pieces form part of the gamma secretase complex. The cleavage of presenilin 1 is prevented by a mutation that leads to the loss of exon 9. With this mutation the presenilin loses its function. It is also known that mutations in the presenilin genes cause familial (genetic) Alzheimer's disease. This manifests itself much earlier than the non-hereditary variant.
The presenilins are also involved in breaking down the protein Notch , which plays an important role in embryonic development.
literature
- Bentahir M. et al .: Presenilin clinical mutations can affect γ-secretase activity by different mechanisms. Journal of Neurochemistry (2006) 96, 732-742
- Spasic D. et al .: Presenilin-1 maintains a nine transmembrane topology throughout the secretary pathway. J. Biol. Chem., Vol. 281, Issue 36, 26569-26577, September 8, 2006