| PSENEN — Presenilin Enhancer | |
|---|---|
| Symbol | PSENEN |
| Full Name | Gamma-Secretase Subunit PEN-2 |
| Chromosome | 19q13.12 |
| NCBI Gene | 55851 |
| Ensembl | ENSG00000105254 |
| OMIM | 607632 |
| UniProt | Q9BXG4 |
| Diseases | Alzheimer's Disease, Familial Alzheimer's Disease |
| Expression | Brain (cerebral cortex, hippocampus), Heart, Liver, Lung, Kidney |
Psenen Gene Presenilin Enhancer is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
PSENEN (Presenilin Enhancer, also known as PEN-2 or Gamma-Secretase Subunit PEN-2) is a gene located on chromosome 19q13.12 that encodes the essential gamma-secretase complex subunit PEN-2 [1]. The gene is approximately 2.5 kilobases and encodes a 101-amino acid polytopic membrane protein with two transmembrane domains [2].
PEN-2 is a critical regulatory component of the gamma-secretase complex, which mediates the proteolytic cleavage of amyloid precursor protein (APP) to generate amyloid-beta (Aβ) peptides [3]. The gamma-secretase complex is composed of four essential subunits: presenilin (catalytic core), nicastrin, APH-1, and PEN-2 [4].
The gamma-secretase complex is an unusual aspartyl protease that cleaves its substrates within their transmembrane domains—a process known as regulated intramembrane proteolysis (RIP) [3].
| Subunit | Gene | Role |
|---|---|---|
| Presenilin | PSEN1/PSEN2 | Catalytic aspartyl protease |
| Nicastrin | NCSTN | Substrate recognition |
| APH-1 | APH1A/APH1B | Complex assembly |
| PEN-2 | PSENEN | Catalytic activation |
PEN-2 plays a critical role in [2]:
The gamma-secretase complex processes APP to generate amyloid-beta peptides [5]:
APP → α-secretase → C83 → γ-secretase → p3 (non-amyloidogenic)
APP → β-secretase → C99 → γ-secretase → Aβ40/Aβ42 (amyloidogenic)
PEN-2 directly influences:
Gamma-secretase (with PEN-2) cleaves over 100 type I transmembrane proteins [6]:
In the brain, PEN-2 is expressed in:
Expression is highest in regions affected by AD pathology: cerebral cortex and hippocampus [7].
PSENEN and the gamma-secretase complex are central to AD pathogenesis [5][8]:
Gamma-secretase is a major therapeutic target for AD:
PSENEN mutations have been linked to acne inversa, a chronic inflammatory skin disease [9]. This suggests PEN-2 has Notch-independent functions in skin homeostasis.
Given Notch pathway involvement:
PEN-2 has a distinctive structure [2]:
The study of Psenen Gene Presenilin Enhancer has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.