Nonsense-mediated mRNA decay factor SMG9 (SMG9)

SMG9 (Nonsense-mediated mRNA decay factor SMG9) is a regulatory subunit of the SMG1 protein kinase complex (SMG1C, composed of SMG1, SMG8, and SMG9) that plays an essential role in the nonsense-mediated mRNA decay (NMD) pathway[1][2][3]. NMD is a surveillance mechanism that selectively degrades mRNAs containing premature stop codons to prevent the accumulation of potentially harmful truncated proteins. SMG9 mediates assembly and stability of the SMG1C complex, and regulates the kinase activity of SMG1 which is required for phosphorylation of UPF1, the central effector of NMD[1][2][3]. Mutations in SMG9 cause heart and brain malformation syndrome and are linked to other neurodevelopmental disorders[2][3]. Besides its role in mRNA quality control, SMG9 may have additional functions in the regulation of responses to cellular stress, DNA damage, and apoptosis[1][3]. Key points: - **Not considered a therapeutic target** (such as a receptor or enzyme), but a fundamental component of mRNA surveillance and quality control[3]. - **No known drug interactions or mechanisms of drug action**; not targeted by approved therapies[3]. - **Primary disease association** is congenital developmental syndromes linked to loss-of-function mutations in SMG9[2][3]. - **Aliases** include other gene identifiers and historical symbols such as C19orf61, FLJ12886, and NEDITPO[3]. - **Protein structure** includes an N-terminal intrinsically disordered region and a C-terminal domain, both necessary for function[1].

Other names

Nonsense-mediated mRNA decay factor SMG9SMG9C19orf61FLJ12886F17127_1HBMSNEDITPOprotein smg-9 homolog