Protein degradation is necessary to recycle proteins that damaged or otherwise aberrant. One way proteins behave aberrantly is by clogging a channel called the translocon, which normally allows proteins to cross the endoplasmic reticulum membrane. The enzyme Hrd1 targets proteins that clog the translocon for degradation. This process is conserved in yeast and humans. Enzymes such as Hrd1 rarely function alone, and the loss of Hrd1 does not completely prevent the destruction of proteins that clog the translocon. We hypothesized that other genes function either with Hrd1 or in a parallel mechanism. In previous work, a genome-wide screen of the yeast genome was performed to identify genes necessary for degradation of translocon-clogging proteins. With large screens, there is a high likelihood of false positives; therefore, small-scale growth assays were performed for validation. The small-scale growth assays validated potential roles for 42 genes in regulating protein degradation at the translocon. We are currently performing biochemical analyses to determine if these 42 genes function in translocon-clogging degradation. Since a protein found in low-density lipoproteins (“bad cholesterol”) is known to clog the translocon, validated genes may represent therapeutic targets for elevated cholesterol.
Cells possess channels that are vital to life. Cells have mechanisms to keep channels unclogged. While a few key players in this process are known, unidentified proteins contribute to channel maintenance. The goal of this work is to identify proteins that maintain channels in an unclogged state.