Proteome-Wide Characterization of Phosphorylation-Induced Conformational and Stability Changes in Breast Cancer

ABSTRACT: Large-scale studies of protein phosphorylation have generally focused on determining the sites and stoichiometry of phosphorylated proteins derived from different biological specimens such as cell lines and tissue samples. While such information is important for understanding the role of phosphorylation in biological systems, it fails to expose the relationship between protein phosphorylation and protein function. Because of the close link between protein function and protein folding stability, knowledge about phosphorylation-induced protein folding stability changes can lead to a better understanding of the functional effects of protein phosphorylation. As part of this work, the Stability of Proteins from Rate of OXidation (SPROX) and Limited Proteolysis (LiP) techniques were utilized to identify phosphorylation-induced conformational and stability changes in proteins derived from a human breast cancer cell line MCF-7. This was accomplished by comparing the conformation properties of proteins in two MCF-7 cell lysates including one that was and one that was not dephosphorylated with alkaline phosphatase. The SPROX technique, which probes the global unfolding/refolding properties of proteins, identified 168 proteins with dephosphorylation-induced stability changes, and the LiPs technique, which probes the more local unfolding/refolding properties of proteins, identified 251 proteins with dephosphorylation-induced stability changes. A total of 49 proteins identified here with dephosphorylation-induced conformational changes, were previously identified in phosphoproteomic studies to be differentially phosphorlyated in different human breast cancer subtypes. A total of 98 proteins identified here overlapped with protein hits previously found to be differentially stabilized in four human breast cancer phenotypes, suggesting that the phosphorylated changes observed here may be disease related. The experimental approach and results reported here create a novel approach for identifying functionally significant PTMs in proteins.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

DISEASE(S): Breast Cancer

SUBMITTER: He Meng  

LAB HEAD: Michael C. Fitzgerald

PROVIDER: PXD007916 | Pride | 2019-11-12

REPOSITORIES: Pride