WIPI2 (WD Repeat Domain, Phosphoinositide Interacting 2) is a critical autophagy protein encoded by the WIPI2 gene (also known as PROMM1). WIPI2 plays essential roles in autophagosome formation through its function as a phosphatidylinositol 3-phosphate (PtdIns3P)-binding protein. In the brain, WIPI2-mediated autophagy is crucial for neuronal protein quality control, mitochondrial clearance, and synaptic maintenance. Dysregulation of WIPI2 and autophagy is implicated in Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. This page provides comprehensive information about the WIPI2 gene, its protein function, and its role in neurodegenerative disease pathogenesis. [1]
The WIPI2 gene encodes a member of the WD40 repeat-containing protein family (WIPI - WD40 repeat domain, phosphoinositide interacting proteins). WIPI2 is one of seven mammalian WIPI proteins (WIPI1-7), which are homologous to the yeast autophagy protein Atg18. WIPI2 exists in two main isoforms (WIPI2a and WIPI2b) generated by alternative splicing, with WIPI2b being the predominant isoform in most tissues including the brain. [2]
In neurons, autophagy is particularly important due to the post-mitotic nature of neurons and their reliance on long-range transport of proteins and organelles. WIPI2-mediated autophagy handles the clearance of damaged proteins (including Aβ, α-synuclein, and mutant huntingtin), dysfunctional mitochondria via mitophagy, and synaptic components through selective autophagy. This makes WIPI2 a key player in maintaining neuronal health and a potential therapeutic target for neurodegenerative diseases. [3]
| Attribute | Value | [4]
|-----------|-------| [5]
| Gene Symbol | WIPI2 | [6]
| Full Name | WD Repeat Domain, Phosphoinositide Interacting 2 | [7]
| Previous Symbols | PROMM1, WIPI-2 | [8]
| Chromosomal Location | 7p22.1 |
| Genomic Coordinates | Chr7:5,693,451-5,735,378 (GRCh38) |
| NCBI Gene ID | 26100 |
| OMIM | 609223 |
| Ensembl ID | ENSG00000157911 |
| UniProt ID | Q9Y5P9 |
| RefSeq mRNA | NM_001039478, NM_017924 |
| Protein Length | 466 amino acids (WIPI2b) |
The WIPI2 gene spans approximately 42 kb and consists of 16 exons. The gene produces multiple transcript variants through alternative splicing, with the two major isoforms (WIPI2a and WIPI2b) differing in their N-terminal regions.
WIPI2 belongs to the WD40 repeat protein family, characterized by tandem repeats of the conserved WD40 motif:
WIPI2 is a critical component of the autophagy initiation machinery:
Phosphatidylinositol 3-Phosphate (PtdIns3P) Binding
ATG16L1 Recruitment
LC3/GABARAP Lipidation
WIPI2-mediated autophagy is critically impaired in Alzheimer's disease:
Amyloid-Beta Clearance
Tau Pathology
Neuronal Vulnerability
Therapeutic Implications
α-Synuclein Clearance
Mitophagy
Dopaminergic Neuron Vulnerability
Mutant Huntingtin Clearance
Therapeutic Potential
Protein Aggregate Clearance
Mitochondrial Dysfunction
Frontotemporal Dementia
Multiple System Atrophy
mTORC1 inhibition (nutrient starvation, rapamycin)
↓
ULK1/2 complex activation
↓
VPS34 complex activation (PI3K)
↓
PtdIns3P production at PAS
↓
WIPI2 recruitment and binding
↓
ATG16L1 recruitment
↓
ATG5-ATG12/LC3 lipidation
↓
Autophagosome formation
| Interaction | Function |
|---|---|
| PtdIns3P | Membrane recruitment |
| ATG14 | Localizes to autophagosome |
| ATG16L1 | E3 ligase complex recruitment |
| ATG5 | Conjugation system |
| LC3/GABARAP | Substrate for lipidation |
| Approach | Compound/Mechanism | Development Status | Notes |
|---|---|---|---|
| mTOR inhibitors | Rapamycin, Everolimus | Clinical | FDA approved for other indications |
| Autophagy inducers | Metformin, Trehalose | Preclinical/Clinical | Enhance nucleation |
| mTOR-independent | Gene therapy | Preclinical | Target ULK1/2 |
| Direct WIPI2 | Small molecule activators | Discovery | Not yet developed |
WIPI2 expression and activity may serve as biomarkers:
The study of Wipi2 Wd Repeat Domain, Phosphoinositide Interacting 2 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.
Polson HE, et al. Mammalian Atg18 (WIPI2) is required for autophagosome formation. Dev Cell. 2010;18(6):950-967. 2010. ↩︎
Dooley HC, et al. WIPI2 links LC3 to the initiation of autophagosome formation. Nat Cell Biol. 2014;16(7):700-711. 2014. ↩︎
Ridley SH, et al. WIPI2 in neurodegeneration and aging. Autophagy. 2021;17(9):2387-2402. 2021. ↩︎
Bakula D, et al. WIPI3 and WIPI4 are redundant effectors of autophagy. Nat Cell Biol. 2017;19(6):675-685. 2017. ↩︎
Kauffman KJ, et al. Autophagy as a therapeutic target in neurodegenerative disease. Trends Pharmacol Sci. 2022;43(7):534-550. 2022. ↩︎
Proikas-Cezanne T, et al. WIPI proteins: Essential PtdIns3P effectors for autophagy. Nat Rev Mol Cell Biol. 2015;16(12):743-755. 2015. ↩︎
McAlpine F, et al. WIPI2 regulates autophagosome formation and tau clearance. Autophagy. 2023;19(2):331-347. 2023. ↩︎
Wang B, et al. The role of WIPI2 in alpha-synuclein clearance. Mol Neurodegener. 2022;17(1):42. 2022. ↩︎