MATR3 (matrin 3) is a nuclear matrix protein that serves multiple regulatory functions in gene expression and cellular homeostasis. The protein plays critical roles in RNA metabolism, including binding to N6-methyladenosine (m6A)-containing mRNAs and contributing to mRNA stability 1. MATR3 functions as a splicing regulator, with its proper expression being essential for maintaining nuclear architecture and chr5 accessibility 2. The protein also participates in DNA damage response pathways and interacts with RNA processing machinery, including components like GANP in the TREX-2 complex 3. Disease-associated mutations in MATR3, particularly the p.Ser85Cys variant, cause autosomal dominant distal myopathy characterized by progressive muscle weakness in hands and feet, often accompanied by rimmed vacuoles on muscle biopsy 45. MATR3 mutations are also associated with amyotrophic lateral sclerosis (ALS), contributing to the growing list of genes implicated in motor neuron degeneration 67. In cancer contexts, MATR3 promotes tumor progression by suppressing type I interferon signaling through m6A-mediated mRNA degradation, particularly affecting DHX58 expression and subsequent immune responses 1. The protein's diverse functions underscore its importance in maintaining cellular integrity and its pathogenic role when disrupted.