Ret Receptor: Functional Consequences of Oncogenic Rearrangements.
Abstract
Ret/ptc2 is a soluble, constitutively active oncogene isolated from human papillary thyroid carcinomas. Sequence analysis of ret/ptc2 indicated that the gene resulted from a reciprocal rearrangement event between the cAMP-dependent protein kinase regulatory subunit Ialpha (RIalpha) and the entire tyrosine kinase domain of the Ret receptor. Using the crystal structure of the insulin receptor tyrosine kinase, we have obtained a working model of the Ret/ptc2 kinase domain. This model was used in conjunction with a microinjection assay and a yeast 2-hybrid screen to: 1) determine that the RIalpha dimerization domain is critical for eliciting the Ret/ptc2 mitogenic response, and 2) to identify a number of tyrosine residues of Ret/ptc2 which are both autophosphorylated and interact with downstream signaling proteins containing src-homology domains such as Grb10, PLCgamma, and a LIM domain containing protein, Enigma. Peptide substrates containing these putative phosphorylated tyrosine residues were synthesized and tested in an in vitro kinase assay using Ret/ptc2 expressed in human kidney 293 cells. We have expressed ret/ptc2 in a acterial expression system to study and characterize the physical properties of the purified protein. In addition we have made chimeras of the epidermal growth factor receptor and insulin receptor which mimic he ret/ptc2 gene to test whether the dimerization domain of RIalpha can activate other receptor tyrosine kinases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1996
- Accession Number
- ADB220347
Entities
People
- Susan S. Taylor
Organizations
- University of California, San Diego