Abstract
Activins, members of the transforming growth factorβ family, are pleiotropic growth and differentiation factors. Activin A induces B-cell apoptosis. To identify the genes responsible for activin-induced apoptosis, we performed retrovirus-mediated gene trap screening in a mouse B-cell line. We identified the rasGAPbinding protein Dok-1 (p62) as an essential molecule that links activin receptors with Smad proteins. In B cells overexpressing Dok-1, activin A-induced apoptotic responses were augmented. The expression of bcl-XL was down-regulated by inhibition of the ras/Erk pathway. Activin stimulation triggered association of Dok-1 with Smad3, as well as association of Smad3 with Smad4. Dok-1 also associated with both the type I and type II activin receptors. Dok-1 has been characterized previously as a tyrosine-phosphorylated protein acting downstream of the protein tyrosine kinase pathway: intriguingly, activin signaling did not induce tyrosine phosphorylation of Dok-1. These findings indicate that Dok-1 acts as an adaptor protein that links the activin receptors with the Smads, suggesting a novel function for Dok-1 in activin signaling leading to B-cell apoptosis.
Original language | English |
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Pages (from-to) | 1684-1694 |
Number of pages | 11 |
Journal | EMBO Journal |
Volume | 21 |
Issue number | 7 |
DOIs | |
Publication status | Published - 02-04-2002 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Neuroscience(all)
- Molecular Biology
- Biochemistry, Genetics and Molecular Biology(all)
- Immunology and Microbiology(all)