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Updated: Aug 12, 2026

An Optimized Protocol for Electrophoretic Mobility Shift Assay Using Infrared Fluorescent Dye-labeled Oligonucleotides
Published on: November 29, 2016
In vivo functional analysis of the Ras exchange factor son of sevenless
C A Karlovich1, L Bonfini, L McCollam
1Department of Biology and Molecular Biology Institute, University of California, Los Angeles 90024, USA.
Abstract:
The Son of sevenless (Sos) protein functions as a guanine nucleotide transfer factor for Ras and interacts with the receptor tyrosine kinase Sevenless through the protein Drk, a homolog of mammalian Grb2. In vivo structure-function analysis revealed that the amino terminus of Sos was essential for its function in flies. A molecule lacking the amino terminus was a potent dominant negative. In contrast, a Sos fragment lacking the Drk binding sites was functional and its activity was dependent on the presence of the Sevenless receptor. Furthermore, membrane localization of Sos was independent of Drk. A possible role for Drk as an activator of Sos is discussed and a Drk-independent interaction between Sos and Sevenless is proposed that is likely mediated by the pleckstrin homology domain within the amino terminus.
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