The intranuclear localization and function of YT521-B is regulated by tyrosine phosphorylation

Ilona Rafalska, Zhaiyi Zhang, Natalya Benderska, Horst Wolff, Annette M. Hartmann, Ruth Brack-Werner, Stefan Stamm

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


YT521-B is a ubiquitously expressed nuclear protein that changes alternative splice site usage in a concentration dependent manner. YT521-B is located in a dynamic nuclear compartment, the YT body. We show that YT521-B is tyrosine phosphorylated by c-Abl in the nucleus. The protein shuttles between nucleus and cytosol, where it can be phosphorylated by c-Src or p59fyn. Tyrosine phosphorylation causes dispersion of YT521-B from YT bodies to the nucleoplasm. Whereas YT bodies are soluble in non-denaturing buffers, the phosphorylated, dispersed form is non-soluble. Non-phosphorylated YT521-B changes alternative splice site selection of the IL-4 receptor, CD44 and SRp20, but phosphorylation of c-Abl minimizes this concentration dependent effect. We propose that tyrosine phosphorylation causes sequestration of YT521-B in an insoluble nuclear form, which abolishes the ability of YT521-B to change alternative splice sites.

Original languageEnglish
Pages (from-to)1535-1549
Number of pages15
JournalHuman Molecular Genetics
Issue number15
StatePublished - Aug 1 2004

Bibliographical note

Funding Information:
We thank Nora Heisterkamp, Pamela Schwartzberg, G. Superti-Furga, A.L. Tyner and J. Zhang for providing expression clones and Andre Gessner for providing c-DNAs. This work was supported by the Deutsche Forschungsgemeinschaft.

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Genetics(clinical)


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