CEF3 (SIIPSGPLK) corresponds to aa 13-21 of the influenza A virus M1 protein. The matrix (M1) protein of influenza A virus is a multifunctional protein that plays essential structural and functional roles in the virus life cycle.

The matrix (M1) protein of influenza A virus is a multifunctional protein that plays essential structural and functional roles in the virus life cycle. It drives virus budding and is the major protein component of the virion, where it forms an intermediate layer between the viral envelope and integral membrane proteins and the genomic ribonucleoproteins (RNPs). It also helps to control the intracellular trafficking of RNPs. These roles are mediated primarily via protein-protein interactions with viral and possibly cellular proteins[1]. The influenza virus M1 is required to induce vRNP nuclear export but that cellular phosphorylation is an additional factor. The influenza virus M1 protein is fundamental to a late event in the virus life cycle-the transfer of vRNPs from the nucleus to the cytosol[2].

[1]. Noton SL, et al. Identification of the domains of the influenza A virus M1 matrix protein required for NP binding, oligomerization and incorporation into virions. J Gen Virol. 2007 Aug;88(Pt 8):2280-90. [2]. Bui M, et al. Role of the influenza virus M1 protein in nuclear export of viral ribonucleoproteins. J Virol. 2000 Feb;74(4):1781-6.