Matrin-3 (UniProt P43243) is encoded by the MATR3 (also known as ALS21, KIAA0723, VCPDM) gene (Gene ID 9782) in human. Matrin-3 is an inner nuclear matrix protein involved in multiple nuclear processes, including DNA double strand break response, DNA replication/repair, chromatin organization, and RNA stability and processing. Matrin-3 contains two RNA recognition motifs (a.a. 398-473/RRM1 and a.a. 496-571/RRM2) that mediate RNA-binding and a DNA-binding zinc finger motif (a.a. 801-832). Matrin-3 is known to interact with the RNA-binding protein TDP-43 and MATR3 gene mutations are linked to amyotrophic lateral sclerosis (ALS). Matrin-3 is also a known target of multiple alpha herpes viruses and is known to be utilized by HIV-1 as a Rev cofactor.