The chapter discusses the cell wall integrity (CWI) signaling pathway in *Saccharomyces cerevisiae*, focusing on its architecture, key components, and regulatory mechanisms. The yeast cell wall is crucial for maintaining cell shape and integrity, particularly during growth and morphogenesis. The CWI pathway is a complex network of signaling molecules and proteins that respond to various stressors, including heat stress, hypo-osmotic shock, and oxidative stress, to maintain cell wall integrity. The core elements of the CWI pathway include cell surface sensors (Wsc1-3, Mid2, Mtf1), the small G-protein Rho1, and a series of effectors such as the Pkc1-MAP kinase cascade, β1,3-glucan synthase (GS), Bnf1 formin protein, Sec3, and Skn7 transcription factor. Rho1, a master regulator of CWI signaling, receives inputs from cell surface sensors and activates multiple effectors. The Pkc1-MAP kinase cascade amplifies the signal from Rho1, leading to the activation of downstream targets. Key targets of Rho1 include Pkc1, which regulates the MAP kinase cascade, GS, which synthesizes β1,3-glucan, and Sec3, which is involved in polarized exocytosis. The chapter also discusses the role of other components such as Bni1 and Bnr1 formin proteins, which nucleate actin filaments, and Skn7, a transcription factor that regulates genes involved in cell wall biogenesis and stress response. The chapter highlights the importance of the CWI pathway in maintaining cell wall integrity and its potential as a target for antifungal drug development. It also explores the interface between the CWI pathway and other signaling pathways, such as the HOG pathway, which responds to osmotic stress, and the Ca2+-signaling pathway, which regulates FKS2 expression, a gene involved in β1,3-glucan synthesis. Overall, the CWI pathway is a sophisticated network that coordinates cell wall remodeling, actin cytoskeleton organization, and stress response, ensuring the survival and proper function of *S. cerevisiae* under various environmental conditions.The chapter discusses the cell wall integrity (CWI) signaling pathway in *Saccharomyces cerevisiae*, focusing on its architecture, key components, and regulatory mechanisms. The yeast cell wall is crucial for maintaining cell shape and integrity, particularly during growth and morphogenesis. The CWI pathway is a complex network of signaling molecules and proteins that respond to various stressors, including heat stress, hypo-osmotic shock, and oxidative stress, to maintain cell wall integrity. The core elements of the CWI pathway include cell surface sensors (Wsc1-3, Mid2, Mtf1), the small G-protein Rho1, and a series of effectors such as the Pkc1-MAP kinase cascade, β1,3-glucan synthase (GS), Bnf1 formin protein, Sec3, and Skn7 transcription factor. Rho1, a master regulator of CWI signaling, receives inputs from cell surface sensors and activates multiple effectors. The Pkc1-MAP kinase cascade amplifies the signal from Rho1, leading to the activation of downstream targets. Key targets of Rho1 include Pkc1, which regulates the MAP kinase cascade, GS, which synthesizes β1,3-glucan, and Sec3, which is involved in polarized exocytosis. The chapter also discusses the role of other components such as Bni1 and Bnr1 formin proteins, which nucleate actin filaments, and Skn7, a transcription factor that regulates genes involved in cell wall biogenesis and stress response. The chapter highlights the importance of the CWI pathway in maintaining cell wall integrity and its potential as a target for antifungal drug development. It also explores the interface between the CWI pathway and other signaling pathways, such as the HOG pathway, which responds to osmotic stress, and the Ca2+-signaling pathway, which regulates FKS2 expression, a gene involved in β1,3-glucan synthesis. Overall, the CWI pathway is a sophisticated network that coordinates cell wall remodeling, actin cytoskeleton organization, and stress response, ensuring the survival and proper function of *S. cerevisiae* under various environmental conditions.