This talk describes how we have been developing and using mass spectrometry-based tools to provide a qualitative and quantitative view of how protein phosphorylation controls cellular processes. Recently we adapted a new hybrid triple quadrupole-linear ion trap mass spectrometer to be used in this work. This instrument operates with exquisite selectivity in the triple quadrupole MS mode and performs high sensitivity peptide sequencing while in the linear ion trap MS mode. This combination has allowed us to identify and monitor the activation of specific phosphorylation sites on individual proteins or in highly complex mixtures. With or without stable isotope tagging we are able to define subsets of in vivo activated phosphorylation sites which are functionally significant in a given pathway. Following this multiple, specific epitopes can be accurately monitored in a highly sensitive assay using mass spectrometry.
This page has been accessed
times since 9/15 /96 .
Last Updated 9/7/2005