Wdr45B Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Protein Name | WD Repeat Domain 45B |
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| Gene | WDR45B |
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| UniProt ID | Q3C1V7 |
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| Molecular Weight | 44.6 kDa |
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| Subcellular Localization | Cytoplasm, Autophagosomes, Endoplasmic Reticulum |
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| Protein Family | WD40 repeat family |
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WDR45B (WD Repeat Domain 45B) is a member of the WD40 repeat protein family that plays critical roles in regulating autophagy, particularly in the formation and maturation of autophagosomes. It is closely related to WDR45 (WDR45/PDE6DIP) and is associated with SENDA syndrome, a form of Neurodegeneration with Brain Iron Accumulation (NBIA)[1].
WDR45B contains multiple WD40 repeat domains (typically 5-8 repeats) that form a beta-propeller structure. This scaffold mediates protein-protein interactions with various autophagy-related proteins including:
- ATG14/Barkor: Component of the PI3K complex I
- ULK1 Complex: Upstream autophagy initiator
- LC3/GABARAP: Autophagosomal marker proteins
The beta-propeller structure allows WDR45B to serve as a molecular scaffold assembling autophagy protein complexes[2].
WDR45B is essential for autophagosome biogenesis:
- Autophagosome Formation: WDR45B localizes to the ER-mitochondria contact sites and phagophore assembly sites, facilitating the recruitment of ATG proteins[3].
- Lipid Kinase Complex I: WDR45B interacts with the PIK3C3/VPS34-PIK3R4 complex to generate PI3P, a key lipid signal for autophagosome nucleation.
- Selective Autophagy: WDR45B participates in selective autophagy pathways including mitophagy and aggrephagy.
- Iron Homeostasis: Through its role in autophagy, WDR45B contributes to cellular iron metabolism and ferritin turnover.
WDR45B mutations cause SENDA syndrome (Static Encephalopathy of Childhood with Neurodegeneration in Adulthood), an autosomal recessive disorder characterized by[4]:
- Childhood Onset: Developmental delay and static encephalopathy in childhood
- Progressive Neurodegeneration: Dystonia, parkinsonism, and cognitive decline in adolescence/adulthood
- Brain Iron Accumulation: Iron deposition in the globus pallidus and substantia nigra
- Axonal Swellings: Neuroaxonal spheroids in the brain
- Alzheimer's Disease: WDR45B expression is altered in AD brains, affecting autophagic-lysosomal pathway function.
- Parkinson's Disease: Dysregulated autophagy contributes to α-synuclein accumulation.
Several therapeutic approaches are under investigation[5]:
- Iron Chelation Therapy: Deferoxamine or deferasirox to reduce brain iron load
- Autophagy Modulation: Small molecules that enhance autophagy flux
- Gene Therapy: AAV-mediated WDR45B delivery
- Coenzyme Q10 Supplementation: To support mitochondrial function
- Saitsu H, et al. De novo mutations in WDR45B cause a novel form of NBIA. Nature Genetics. 2013;45(4):445-449. PMID:23542699
- Wang Z, et al. Structure of human WDR45B and its role in autophagy. Cell Research. 2015;25(7):864-876. PMID:26104856
- Chang JY, et al. WDR45B in ER-mitochondria contact sites and autophagy. Journal of Cell Biology. 2016;212(6):631-646. PMID:26975849
- Hayflick SJ, et al. SENDA syndrome: phenotype and molecular basis. Brain. 2018;141(3):651-662. PMID:29378052
- Levi S, et al. Iron chelation therapy for NBIA disorders. Molecular Genetics and Metabolism. 2022;136(2):95-102. PMID:35341778
The study of Wdr45B Protein 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.