Srp20-Human Alternative Splicing Factor: Difference between revisions

In addition to RNA recognition and alternative splicing functions, SRp20 has been shown to associate with Tip Associated Protein (TAP), an mRNA export factor, to promote transport of bound mRNA out of the nucleus for eventual translation. In particular, SRp20 promotes the export of H2A histone mRNA by binding the CAUC consensus sequence on the mRNA and TAP. Previous experiments show that SRp20 binding TAP is dependent on the presence of both the <scene name='78/786034/Rrmredgreen/3'>SRp20</scene>> and a short arginine-rich C-terminal segment after the RRM (aa 1-83 and 84-90 respectively) ('''Figure 1'''). Previous research also shows that mutation of any one of the three arginine residues between residues 84-90 to glutamate prevents TAP binding, indicative of the importance of these arginine residues in TAP association. The structure is only solved to residue 86 so only the <scene name='78/786034/Arginine1/4'>first arginine residue</scene> is present. The same study also found that transfer of the TAP-binding motif to a non-functional REF2 RRM still allowed for TAP binding and nuclear export of the target protein, suggesting that not only is the TAP binding motif transferable, but it also does not depend on interaction with the host RRM to retain function<ref name="Hargous">PMID:17036044</ref>.