Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Biochemistry and Molecular Biology

First Advisor

Dae Joon Kim

Second Advisor

Robert Dearth

Third Advisor

Yonghong Zhang


Ultraviolet B (UVB) radiation can distort cellular homeostasis and predispose the skin to carcinogenesis. Amongst the deteriorating effects of the sun’s UVB radiation on cellular homeostasis is the formation of DNA photoproducts such as cyclobutene pyrimidine dimers. These photoproducts can cause significant changes in the structure and conformation of the DNA, inducing gene mutations which may accumulate to trigger the formation of skin cancer. Photoproducts are typically repaired by nucleotide excision repair. Notwithstanding, when the repair mechanism fails, apoptosis ensues to prevent the accumulation of mutations and to restore cellular homeostasis. We have identified T-cell protein tyrosine phosphatase (TC-PTP) as a positive regulator of UVB-induced apoptosis and our findings suggest that TC-PTP protects keratinocytes from UVB-induced skin carcinogenesis by inhibiting autophagy-mediated cell survival and proliferation of damaged keratinocytes. This implies that design of therapeutics to target TC-PTP could help in the prevention and treatment of skin cancers.


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