The intestinal barrier is a critical component of the gastrointestinal tract, functioning as a physical and chemical barrier against external pathogens and maintaining symbiosis with gut microbiota. Tight junction proteins, including occludin, claudins, and zonula occludens (ZO), are essential for maintaining epithelial barrier integrity. These proteins, along with intracellular signaling pathways and extracellular stimuli such as cytokines and small GTPases, dynamically regulate barrier function. Disruption of these regulatory mechanisms can lead to compromised barrier integrity, contributing to diseases like inflammatory bowel disease (IBD), obesity, and metabolic disorders. The intestinal epithelial barrier is composed of specialized cells, including enterocytes, Paneth cells, goblet cells, and microfold cells, each playing a role in maintaining barrier function and immune homeostasis. The barrier is regulated by tight junction proteins, which form a complex network with the cytoskeleton and other proteins to maintain structural integrity. Dysregulation of these proteins can lead to increased permeability, allowing harmful substances to enter the body and triggering immune responses. Tight junction proteins are regulated by various signaling pathways, including those involving cytokines such as TNF-α and IFN-γ, which can disrupt barrier integrity. Post-translational modifications, such as phosphorylation, also play a crucial role in regulating tight junction function. For example, occludin phosphorylation is involved in the regulation of tight junction permeability and barrier function. In pathological conditions such as IBD, obesity, and metabolic disorders, the intestinal barrier is often compromised, leading to increased permeability and the translocation of gut microbiota-derived molecules, which can contribute to systemic inflammation and disease progression. The regulation of tight junction proteins and barrier function is therefore a key area of research for developing therapeutic strategies to treat these conditions. Understanding the molecular mechanisms underlying barrier regulation is essential for developing novel therapeutic approaches to improve intestinal barrier integrity and prevent disease.The intestinal barrier is a critical component of the gastrointestinal tract, functioning as a physical and chemical barrier against external pathogens and maintaining symbiosis with gut microbiota. Tight junction proteins, including occludin, claudins, and zonula occludens (ZO), are essential for maintaining epithelial barrier integrity. These proteins, along with intracellular signaling pathways and extracellular stimuli such as cytokines and small GTPases, dynamically regulate barrier function. Disruption of these regulatory mechanisms can lead to compromised barrier integrity, contributing to diseases like inflammatory bowel disease (IBD), obesity, and metabolic disorders. The intestinal epithelial barrier is composed of specialized cells, including enterocytes, Paneth cells, goblet cells, and microfold cells, each playing a role in maintaining barrier function and immune homeostasis. The barrier is regulated by tight junction proteins, which form a complex network with the cytoskeleton and other proteins to maintain structural integrity. Dysregulation of these proteins can lead to increased permeability, allowing harmful substances to enter the body and triggering immune responses. Tight junction proteins are regulated by various signaling pathways, including those involving cytokines such as TNF-α and IFN-γ, which can disrupt barrier integrity. Post-translational modifications, such as phosphorylation, also play a crucial role in regulating tight junction function. For example, occludin phosphorylation is involved in the regulation of tight junction permeability and barrier function. In pathological conditions such as IBD, obesity, and metabolic disorders, the intestinal barrier is often compromised, leading to increased permeability and the translocation of gut microbiota-derived molecules, which can contribute to systemic inflammation and disease progression. The regulation of tight junction proteins and barrier function is therefore a key area of research for developing therapeutic strategies to treat these conditions. Understanding the molecular mechanisms underlying barrier regulation is essential for developing novel therapeutic approaches to improve intestinal barrier integrity and prevent disease.