The gene <i>PPP1R1B</i> expresses t-Darpp, a protein that activates protein kinase A and the AKT pathway in breast cancer cells. t-Darpp, when overexpressed in breast cancer cells, also confers resistance to trastuzumab, a therapeutic that binds to the Her2 receptor. Although t-Darpp expression is relatively high in gastric, breast and colon cancers, its structure is unknown. Human t-Darpp has two cysteine residues that can be exploited to explore t-Darpp structure, Cys36 and Cys119. Methoxypolyethylene glycol-maleimide (Mal-PEG) was used to determine whether recombinant t-Darpp cysteine thiols are on the surface of the protein and to find out if they are reversibly oxidized. This study shows that the two cysteine thiols are either buried or oxidized. Further work will be conducted to distinguish between these two possibilities.

Assessing cysteine residue thiol status in T-Darpp, a protein involved in chemoresistance

253rd National Meeting (2017)

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