Location

Portland State University

Start Date

2-5-2018 11:00 AM

End Date

2-5-2018 1:00 PM

Subjects

Ligases, Ubiquitin, Cell cycle, Biochemistry -- Cell differentiation

Abstract

Cyclin E is an evolutionarily conserved protein whose essential function is to promote the cell cycle transition from G1 to S phase. Cul3 is the main component of the pathway that controls Cyclin E ubiquitination, playing an important role in the normal cell cycle regulation in vivo. The binding between Cul3 and Cyclin E does not occur directly and requires a BTB domain protein to act as a substrate adaptor. The substrate linker responsible for this binding is known as RhoBTB3. Muf1, a largely uncharacterized protein of unknown function, is able to bind to RhoBTB3 directly indicating that it might be responsible for an important but as of yet unknown role within the cell. Our hypothesis is that Muf1 can regulate the binding between Cul3 and RhoBTB3, altering its role and making the BTB domain protein a substrate instead of an adaptor, which leads to its degradation. We designed two different models to explain Muf1 role and to understand how this protein can interfere with the ubiquitination and degradation of RhoBTB3. Our first model hypothesizes that Muf1 displaces RhoBTB3 and causes its degradation while the second model proposes that Muf1 acts like a B/C adaptor for Cul3 and helps to tag substrates for degradation by the proteasome. In order to test them and determine how Muf1 affects and binds to RhoBTB3, we are planning to transfect the proteins into HEK293 cells followed by western blots, and immunoprecipitation assays.

Persistent Identifier

http://archives.pdx.edu/ds/psu/25099

Included in

Biology Commons

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May 2nd, 11:00 AM May 2nd, 1:00 PM

Unique E3 Ligase Complexes Regulate Levels of Cyclin E

Portland State University

Cyclin E is an evolutionarily conserved protein whose essential function is to promote the cell cycle transition from G1 to S phase. Cul3 is the main component of the pathway that controls Cyclin E ubiquitination, playing an important role in the normal cell cycle regulation in vivo. The binding between Cul3 and Cyclin E does not occur directly and requires a BTB domain protein to act as a substrate adaptor. The substrate linker responsible for this binding is known as RhoBTB3. Muf1, a largely uncharacterized protein of unknown function, is able to bind to RhoBTB3 directly indicating that it might be responsible for an important but as of yet unknown role within the cell. Our hypothesis is that Muf1 can regulate the binding between Cul3 and RhoBTB3, altering its role and making the BTB domain protein a substrate instead of an adaptor, which leads to its degradation. We designed two different models to explain Muf1 role and to understand how this protein can interfere with the ubiquitination and degradation of RhoBTB3. Our first model hypothesizes that Muf1 displaces RhoBTB3 and causes its degradation while the second model proposes that Muf1 acts like a B/C adaptor for Cul3 and helps to tag substrates for degradation by the proteasome. In order to test them and determine how Muf1 affects and binds to RhoBTB3, we are planning to transfect the proteins into HEK293 cells followed by western blots, and immunoprecipitation assays.