Elucidation of overexpression of Transcription factor, TAF7 in Eukaryotic Cell

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Abstract:

TAF7 is a conserved transcription factor and core subunit of the TFIID complex that is overexpressed in multiple cancers, although the mechanism underlying its upregulation remains unclear. The ubiquitin–proteasome system (UPS) regulates protein stability through ubiquitin-mediated modification and proteasomal degradation and may therefore control TAF7 abundance. Determining whether the UPS regulates TAF7 stability will clarify the basis of its overexpression and may reveal novel therapeutic targets in cancer. Our aims was to determine whether the UPS regulates TAF7 abundance in the yeast (Saccharomyces cerevisiae). To address this question, we performed biochemical assays to assess TAF7 ubiquitination and proteasome-dependent turnover. Ni²⁺-NTA pull-down assays in S. cerevisiae demonstrated that TAF7 undergoes polyubiquitination. However, inhibition of the 26S proteasome using MG132 did not alter TAF7 protein levels. These findings indicate that although TAF7 is polyubiquitinated, it is not targeted for proteasomal degradation. Our results suggest that TAF7 may be regulated through non-proteolytic ubiquitination rather than degradation by the 26S proteasome. Such ubiquitination could influence TAF7 function, transcriptional activity, subcellular localization, or protein–protein interactions instead of controlling its stability. This regulatory mechanism may contribute to TAF7 dysregulation in cancer cells.Future studies will examine whether TAF7 is similarly ubiquitinated in human cancer cell lines, identify the E3 ubiquitin ligase(s) responsible for its modification, and determine how ubiquitination affects TAF7-dependent transcription and cancer-related cellular phenotypes.

Document Type

abstracts (summaries)

Language

English

Rights

http://rightsstatements.org/vocab/InC/1.0/

License

http://creativecommons.org/licenses/by/4.0/

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Elucidation of overexpression of Transcription factor, TAF7 in Eukaryotic Cell

Abstract:

TAF7 is a conserved transcription factor and core subunit of the TFIID complex that is overexpressed in multiple cancers, although the mechanism underlying its upregulation remains unclear. The ubiquitin–proteasome system (UPS) regulates protein stability through ubiquitin-mediated modification and proteasomal degradation and may therefore control TAF7 abundance. Determining whether the UPS regulates TAF7 stability will clarify the basis of its overexpression and may reveal novel therapeutic targets in cancer. Our aims was to determine whether the UPS regulates TAF7 abundance in the yeast (Saccharomyces cerevisiae). To address this question, we performed biochemical assays to assess TAF7 ubiquitination and proteasome-dependent turnover. Ni²⁺-NTA pull-down assays in S. cerevisiae demonstrated that TAF7 undergoes polyubiquitination. However, inhibition of the 26S proteasome using MG132 did not alter TAF7 protein levels. These findings indicate that although TAF7 is polyubiquitinated, it is not targeted for proteasomal degradation. Our results suggest that TAF7 may be regulated through non-proteolytic ubiquitination rather than degradation by the 26S proteasome. Such ubiquitination could influence TAF7 function, transcriptional activity, subcellular localization, or protein–protein interactions instead of controlling its stability. This regulatory mechanism may contribute to TAF7 dysregulation in cancer cells.Future studies will examine whether TAF7 is similarly ubiquitinated in human cancer cell lines, identify the E3 ubiquitin ligase(s) responsible for its modification, and determine how ubiquitination affects TAF7-dependent transcription and cancer-related cellular phenotypes.