Breast Tumor Kinase Signaling in Breast Cancer
Abstract
We previously demonstrated that the breast tumor kinase Brk can phosphorylate and inhibit the RNA-binding protein Sam68, which plays important roles in RNA metabolism associated with growth. Two novel Sam68-like mammalian proteins SLMl and SLM2 were identified, and cotransfection of NMuMG cells with different Brk expression constructs and either GFP-SLM1 or GFP-SLM2 revealed a direct correlation between Brk activity and the level of SLM1 and SLM2 phosphorylation. Mutation of the terminal tyrosine in Brk (Brk Y-F) increased the level of SLM protein phosphorylation. Localization of tyrosine phosphorylated proteins was examined in NMuMG cells cotransfected with Brk constructs and GFP-tagged substrates. Interestingly phosphotyrosine immunoreactivity was restricted to the nucleus and co-localized with the GFP-tagged nuclear substrates only when Brk Y-F was expressed. Expression of wild type Brk resulted in phosphorylation of cytoplasmic and nuclear proteins. This suggests a role for the carboxy terminal tyrosine in localization of Brk.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2003
- Accession Number
- ADA417996
Entities
People
- Angela L. Tyner
Organizations
- University of Illinois at Chicago