WTAP Protein is a protein. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target. [1]
WTAP (Wilms' Tumor 1-Associated Protein) is a 399-amino acid nuclear protein that serves as a regulatory subunit of the N6-methyladenosine (m6A) methyltransferase complex. Originally identified as a tumor suppressor interacting with WT1, WTAP plays essential roles in RNA processing and m6A modification. The protein contains an N-terminal region rich in proline and glutamine residues that mediates protein-protein interactions, and a C-terminal region that contributes to RNA binding. WTAP localizes to nuclear speckles, where the m6A methyltransferase complex is assembled and regulated. WTAP does not possess catalytic activity but is essential for the nuclear localization of the METTL3-METTL14 heterodimer and for recruiting additional regulatory proteins to the complex. WTAP interacts with multiple splicing factors and RNA-binding proteins, linking m6A modification to alternative splicing regulation. The protein forms a stable complex with METTL3 and METTL14, and mutations affecting any component disrupt complex formation and catalytic activity.
WTAP plays important roles in RNA metabolism and gene expression in the nervous system:
WTAP is expressed in neurons and glial cells throughout the brain, with particularly high expression in the hippocampus and cortex. Its localization to nuclear speckles suggests important roles in co-transcriptional RNA processing.
WTAP expression is altered in Alzheimer's disease brains, contributing to dysregulated m6A modification of disease-relevant transcripts. Studies show reduced WTAP levels in AD brains, which correlates with decreased m6A modification of APP and tau mRNAs. This dysregulation affects amyloid-beta production and tau pathology. WTAP also interacts with splicing factors that regulate the alternative splicing of APP and tau isoforms, adding another layer of complexity to its role in AD.
In Parkinson's disease, WTAP and the m6A pathway regulate the translation of mitochondrial function genes and transcripts involved in alpha-synuclein metabolism. WTAP knockdown in dopaminergic neurons affects cell viability and susceptibility to PD-related stress. The m6A reader proteins show altered expression in PD brains, indicating disrupted m6A homeostasis in dopaminergic neurons.
WTAP dysfunction has been implicated in epilepsy pathogenesis. Altered m6A modification of ion channel and neurotransmitter receptor mRNAs affects neuronal excitability. Studies in epilepsy models show that WTAP expression is upregulated during seizures, suggesting a role in the acute stress response. Therapeutic targeting of the m6A pathway may have potential for seizure control.
WTAP variants have been associated with neurodevelopmental disorders including intellectual disability and autism spectrum disorders. These findings highlight the essential role of WTAP and m6A methylation in human brain development. The phenotypic overlap with METTL3 and METTL14-related disorders confirms the importance of the intact methyltransferase complex.
WTAP represents a potential therapeutic target:
Knuckles P, et al. WTAP controls naive pluripotency through m6A-dependent translation regulation. Cell Stem Cell. 2022. ↩︎