Volume 4, Issue 4 (2023) – 9 articles
Cover Picture: In endocrine cells and neurons, hormones and neurotrophic factors are packaged in dense core secretory vesicles (DCVs) which are trafficked to the plasma membrane and released in a regulated manner upon stimulation. This is known as the regulated secretory pathway (RSP). Other secretory proteins from these cells are released constitutively. More recently, hormones, trophic factors and other regulated secretory proteins have been found in extracellular vesicles (EVs) secreted from endocrine and neuronal cells. The molecular mechanisms of sorting and packaging of regulated secretory proteins at the trans-Golgi network into DCVs followed by their trafficking and secretion are well known. However, the mechanism of how hormones and trophic factors are sorted and packaged into EVs has not been well studied. A possible routing mechanism involves the budding of vesicles containing these proteins at the trans Golgi network, which then fuse with endosomes followed by formation of intralumenal vesicles (ILVs) which then become EVs in the multivesicular body. Hormones and neurotrophic factors secreted via the RSP can potentially also be endocytosed into endosomes and then be packaged into EVs via ILVs. Hormones and trophic factors secreted from DCVs bind to specific membrane receptors in recipient cells, followed by signal transduction to mediate biological functions. On the other hand, EVs carrying these cargo proteins are taken by recipient cells and released into the into the cytoplasm to exert its physiological effects. These RSP proteins secreted by the two modes could have different functions.
view this paper 
