METTL14 Protein is a protein. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target. [1]
METTL14 (Methyltransferase Like 14) is a 456-amino acid protein that forms the substrate recognition component of the m6A methyltransferase complex. While METTL3 provides the catalytic activity, METTL14 is essential for complex formation, substrate binding, and proper cellular localization. The protein contains an N-terminal region that mediates interactions with METTL3 and WTAP, and a C-terminal methyltransferase-like domain that, despite being catalytically inactive, contributes to RNA binding. The METTL3-METTL14 heterodimer forms a saddle-shaped structure that recognizes specific RNA sequence motifs (DRACH) and positions the adenine substrate within the active site of METTL3. METTL14 contains an extended loop region that contacts the RNA substrate and contributes to substrate specificity. The protein forms a stable heterodimer with METTL3 in a 1:1 ratio, and this heterodimer further assembles with WTAP into the larger methyltransferase complex (MACOM/MAC).
METTL14 plays essential roles in RNA metabolism in the nervous system:
METTL14 is expressed throughout the brain, with high expression in the hippocampus, cortex, and cerebellum. Like METTL3, its expression is dynamically regulated during development and in response to neural activity.
METTL14 dysfunction contributes to Alzheimer's disease pathogenesis through altered m6A modification of key AD-related transcripts. Studies show reduced METTL14 expression in AD brains, leading to decreased m6A levels on amyloid precursor protein (APP) and tau mRNAs. This dysregulation affects APP processing and tau phosphorylation, contributing to amyloid and tau pathology. The m6A reader YTHDF1, which promotes translation, shows altered expression in AD, creating a complex dysregulation of m6A-mediated translation control.
In Parkinson's disease, METTL14 plays a role in regulating the translation of mitochondrial function and autophagy-related transcripts. Alpha-synuclein mRNA is modified by m6A, and METTL14 activity affects its translation efficiency. Dysregulated m6A methylation contributes to mitochondrial dysfunction in dopaminergic neurons, a key feature of PD pathogenesis.
Following cerebral ischemia, METTL14 expression is altered, affecting the m6A modification of stress response genes. The m6A pathway regulates neuronal survival after ischemic injury, with METTL14 knockdown protecting against ischemia-reperfusion injury in some models. This suggests potential therapeutic applications in stroke treatment.
Loss-of-function variants in METTL14 cause neurodevelopmental disorders with intellectual disability and speech impairment, highlighting the essential role of m6A methylation in human brain development. The phenotype overlaps with METTL3-related disorders, confirming the importance of the intact methyltransferase complex.
Therapeutic modulation of METTL14 is being explored:
Yao Y, et al. METTL14 deficiency reduces amyloid-beta generation through regulating APP mRNA splicing. Alzheimer's Research & Therapy. 2022. ↩︎