Exocytosis and protein secretion pathways

This presentation will examine exocytosis and protein secretion pathways with a focus on the fundamental steps of exocytosis, including how proteins are synthesized, processed, and transported from the endoplasmic reticulum to the Golgi apparatus and ultimately secreted at the plasma membrane. We will discuss the different pathways of exocytosis, constitutive and regulated, highlighting their key roles in various cell types and physiological processes. Additionally, we will explore how disruptions in exocytosis contribute to diseases and examine important biological examples such as insulin release and neurotransmitter secretion. Exocytosis is a central biological process in which proteins and other molecules are secreted from cells, essential for communication, tissue growth, and homeostasis in both animals and plants. It involves fusion of membrane bound vesicles with the plasma membrane, releasing cargo into the extracellular space. This process includes various exocytosis pathways, protein transport from synthesis to secretion, the mechanisms regulating secretion and disease implications when this process malfunctions. The journey of a secreted protein begins in the rough endoplasmic reticulum, ER, where ribosomes translate MRNA into polypeptides. After synthesis, proteins enter the ER to fold, undergo modifications, and are checked for quality. Correctly folded proteins are packaged into cop two coated vesicles that bud from the ER to the Golgi apparatus.