| Analysis of Protein Tyrosine Phosphatases in Epidermal Growth Factor Receptor Pathway using a Novel Substrate Trapping Mutant Strategy
Crucial role of kinases in signaling cascades has been well investigated and documented. Role of phosphatases in signaling is poorly understood because of the experimental difficulties in studying them. At IOB, scientists are investigating protein tyrosine phosphatases involved in EGF receptor signaling pathway and elucidating their role in EGF receptor signaling using a variety of functional approaches. The knowledge gained from the study will be applied to cancers where epidermal growth factor signaling is known to be aberrant such as lung and breast cancers.
The development of therapeutic approaches for the treatment of diseases is now being based on understanding the intricacies of complex cell signaling pathways. It is well known that kinases play a crucial role in the signaling cascade of any pathway. The targets of these kinases are proteins and other biomolecules, which undergo reversible phosphorylation. This implies the fact that phosphatases, the biochemical counterparts of kinases play an equally important role in the signaling cascade. Phosphatases have long been underestimated for their role in signaling pathways. Recent findings from various labs report the role of phosphatases in tumorigenesis. However, the role of phosphatases in signaling in general is only poorly understood. This is due, in part, to the experimental difficulties associated with studying phosphatases as opposed to kinases. Epidermal Growth factor Receptor tyrosine kinase has long been identified as the promising target for cancer therapy. Phosphatases are potential kinase inhibitors and exploring its role in EGFR pathway will give us new insights in drug targeting. Previous large-scale computational study of PTPases carried out in our lab led to the identification of several novel members of the tyrosine phosphatases family and novel transcript variants.
In this study, using a novel approach, we propose to identify the role of these novel phosphatases and other less studied phosphatases in the EGFR signal transduction pathway. We aim to achieve this study by probing the possible interaction of
these phosphatases with EGFR. Yeast two hybrid approach using substrate-trapping mutants will be undertaken to identify the PTPases that associate with EGFR. In vivo and in vitro interaction studies will identify the role of these molecules in human cell culture systems. Finally, the functional role of these novel interactors will be investigated in mammalian cell lines by using promoter based luciferase assays.
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