[
International Worm Meeting,
2021]
The 26S proteasome is a multi-subunit protein complex that is canonically known for its ability to degrade proteins in cells and maintain protein homeostasis. It is composed of highly conserved protein subunits arranged into two 19S regulatory particles (RP) capping a 20S core catalytic particle (CP). Recent evidence shows specific proteasome subunits play tissue specific and/or non-proteolytic roles in various organisms. Historically, models such as yeast and mammalian cell lines have been used to characterize proteasome assembly and function. However, these unicellular models have limitations in comprehensively understanding the wide range of roles that various proteasome subunits might be playing in different tissues and developmental stages. We have identified specific 19S RP proteasome subunits in C. elegans that play previously unknown roles in the germ line. We will show that certain 19S RP subunits genetically interact with a major C. elegans meiotic kinase, WEE-1.3, and are required for proper germ line localization of WEE-1.3. Importantly we demonstrate that this role in WEE-1.3 localization is not related to the proteolytic function of the proteasome. To help elucidate individual proteasome subunits functions, we have endogenously tagged 19S RP lid subunits with GFP or OLLAS using CRISPR. This has revealed many novel results, including identification of subunit tissue specificity and the dynamics of proteasome assembly. We will show that the two isoforms of the essential 19S RP proteasome subunit RPN-6.1 are expressed in a tissue specific manner in the hermaphrodite. We will also demonstrate that the 19S RP subunits RPN-6.1 and RPN-7 are crucial for the nuclear localization of the lid subunits RPN-8 and RPN-9 in C. elegans oocytes. Collectively, our data supports the premise that certain 19S RP proteasome subunits are playing tissue specific roles, especially in the germ line. We propose C. elegans as a versatile multicellular model to study the diverse proteolytic and non-proteolytic roles that proteasome subunits play in vivo.