Splicing modulators act at the branch point adenosine binding pocket defined by the PHF5A-SF3b complex.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28541300.
- Also identified by DOI 10.1038/ncomms15522 and PMC identifier 5458519.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Pladienolide, herboxidiene and spliceostatin have been identified as splicing modulators that target SF3B1 in the SF3b subcomplex. Here we report that PHF5A, another component of this subcomplex, is also targeted by these compounds. Mutations in PHF5A-Y36, SF3B1-K1071, SF3B1-R1074 and SF3B1-V1078 confer resistance to these modulators, suggesting a common interaction site. RNA-seq analysis reveals that PHF5A-Y36C has minimal effect on basal splicing but inhibits the global action of splicing modulators. Moreover, PHF5A-Y36C alters splicing modulator-induced intron-retention/exon-skipping profile, which correlates with the differential GC content between adjacent introns and exons. We determine the crystal structure of human PHF5A demonstrating that Y36 is located on a highly conserved surface. Analysis of the cryo-EM spliceosome B<sup>act</sup> complex shows that the resistance mutations cluster in a pocket surrounding the branch point adenosine, suggesting a competitive mode of action. Collectively, we propose that PHF5A-SF3B1 forms a central node for binding to these splicing modulators.
Medical subject headings
- Adenosine
- Alternative Splicing
- Carrier Proteins
- Phosphoproteins
- RNA Splicing Factors