The STRIPAK (STRiatin Interacting Phosphatase And Kinase) Complex is an evolutionarily conserved Protein Phosphatase 2A (PP2A) holoenzyme complex found in all metazoans. How the STRIPAK complex functions in a living organism is therefore of great interest. While substantial effort has been expended to elucidate the in vitro interactions an assembly of STRIPAK components, the roles of STRIPAK in vivo remain poorly illuminated. Chapter 1 of this thesis briefly reviews what is known about STRIPAK function in various standard model organisms, and identifies several key unanswered questions addressed within the remainder of this thesis. In Chapter 2 I use C. elegans as a model organism to uncover functions of STRIPAK during animal development. As early as the first cytokinetic event, I show that the STRIPAK components FARL-11/Strip and CASH-1/Striatin function to prevent ectopic contractile events at the cell cortex. Given that Striatin is the structural backbone of the STRIPAK complex, I go on to demonstrate that individual domains of CASH-1 are essential for its function, not only by affecting the localization pattern of FARL-11, but also by regulating clustering and activity of the Centralspindlin component ZEN-4/MKLP1. The most parsimonious model based on my results is that STRIPAK, via its enzymatic activity as a phosphatase holoenzyme, may regulate the phosphostatus, and hence activity, of ZEN-4. In Chapter 3, I show that CASH-1/Striatin and FARL-11/Strip are both necessary for organizing sarcomeres; in particular, STRIPAK is necessary for spatial localization and organization of the sarcoplasmic reticulum in body wall muscle. In Chapter 4 I suggest areas for future study, including further exploration of the intriguing DLG-1/AJM-1-dependent localization of STRIPAK components at epidermal junctions during embryonic elongation, when the epidermis is subject to mechanical tension. The Appendices of this thesis document additional work I have done to generate reagents for single-molecule mechanobiological analysis of HMP-1/⍺-catenin, and to explore the role of salt-bridge-dependent stabilization of the HMP-1 M domain in recruitment of SRGP-1/srGAP at junctions during morphogenesis. Taken together, these experiments make novel contributions to our understanding of key conserved molecular complexes that regulate the cell cortex and cell-cell junctions in all metazoans.