This entry represents RNA guanine-N7 methyltransferase activating subunit (RAMAC; also known as RNMT-activating mini protein, RAM), which is an essential component of the mRNA-capping methyltransferase RNMT:RAMAC complex required for mRNA cap methylation [, ]. RAM consists of an N-terminal RNMT-activating domain and a C-terminal RNA-binding domain [].In eukaryotes, the 7-methylguanosine cap added to the 5' end of mRNA is required for efficient gene expression. In mammals, methylation of the guanosine cap requires RNMT (RNA guanine-7 methyltransferase) []. The interaction between RNMT and RAM enhances the mRNA binding capacity and cap methyltransferase activity [].