Selective inhibition of the function of tyrosine-phosphorylated STAT3 with a phosphorylation site-specific intrabody
Abstract
In response to a variety of extracellular stimuli, signal transducer and activator of transcription 3 (STAT3) is phosphorylated on Tyr705 (pYSTAT3) or Ser727 (pSSTAT3), and signal transmission by those stimuli depend on pYSTAT3 as well as pSSTAT3 and unphosphorylated protein (USTAT3). Here we prepared an intrabody (an antibody that is expressed within the cell) that binds specifically to the tyrosine-phosphorylated site of pYSTAT3 and demonstrated that the engineered intrabody is able to block selectively the downstream effects of pYSTAT3 without influencing those of pSSTAT3 and USTAT3 in cultured cells as well as mouse liver. Our results demonstrate the potential of intrabodies as tools to dissect the cellular functions of specific modified forms of proteins that exist as multiple species.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- April 2014
- DOI:
- 10.1073/pnas.1316815111
- Bibcode:
- 2014PNAS..111.6269K