Nucleocytoplasmic Shuttling of Polypyrimidine Tract-binding Protein Is Uncoupled from RNA Export

Polypyrimidine Tract-Binding Protein Is

Polypyrimidine-tract-binding protein: a multifunctional RNA-binding protein.

PTB (polypyrimidine-tract-binding protein) is a ubiquitous RNA-binding protein. It was originally identified as a protein with a role in splicing but it is now known to function in a large number of diverse cellular processes including polyadenylation, mRNA stability and translation initiation. Specificity of PTB function is achieved by a combination of changes in the cellular localization of t...

Tract-Binding Protein Is Involved in A Complex Containing Polypyrimidine

Facilitated nucleocytoplasmic shuttling of the Ran binding protein RanBP1.

The Ran binding protein RanBP1 is localized to the cytosol of interphase cells. A leucine-rich nuclear export signal (NES) near the C terminus of RanBP1 is essential to maintain this distribution. We now show that RanBP1 accumulates in nuclei of cells treated with the export inhibitor, leptomycin B, and collapse of the nucleocytoplasmic Ran:GTP gradient leads to equilibration of RanBP1 across t...

Exon repression by polypyrimidine tract binding protein.

Polypyrimidine tract binding protein (PTB) is known to silence the splicing of many alternative exons. However, exons repressed by PTB are affected by other RNA regulatory elements and proteins. This makes it difficult to dissect the structure of the pre-mRNP complexes that silence splicing, and to understand the role of PTB in this process. We determined the minimal requirements for PTB-mediat...