Grsf1 (G-rich RNA sequence binding factor 1) is an RNA-binding protein, which belongs to the F/H family of heterogeneous ribonucleoprotein, and contains three quasi-RNA recognition motifs (qRRM). These domains enable it to bind to RNA molecules, and it interacts with various RNA molecules, including mRNA, lncRNA and circRNA, affecting the metabolism and function of these RNAs. The expression of GRSF1 is closely related to cell senescence. It was found that with the aging of cells, the methylation level in the promoter region of GRSF1 gene increased, which led to the decrease of its expression. The decrease of GRSF1 expression is related to the activation of various aging-related markers and the increase of the secretion of aging-related secretory phenotype (SASP) factors, which may play a key role in maintaining the normal function of cells and delaying the aging process. GRSF1 also plays an important role in the mitochondria of cells. It interacts with RNase P and participates in the processing of mitochondrial RNA, including the processing of classical and tRNA-free RNA precursors. In the case of GRSF1 deletion, the primary transcript of mitochondrial RNA is cut abnormally, which leads to the decrease of the expression of mitochondrial coding protein, and then causes mitochondrial dysfunction. Isoform 1, 53 kDa, located in mitochondria; Isoform 2, 36 kDa, located in cytoplasm.