Exosomenbildung

Exosomenbildung refers to the biological process by which cells generate and release exosomes. Exosomes are small extracellular vesicles, typically ranging from 30 to 150 nanometers in diameter, that are secreted by most cell types. The formation of exosomes begins within the cell when the plasma membrane invaginates to form early endosomes. These early endosomes then mature into late endosomes, which are also known as multivesicular bodies (MVBs). Within the MVBs, further invaginations of the endosomal membrane form intraluminal vesicles (ILVs), which are essentially nascent exosomes. These ILVs are enclosed within the lumen of the MVBs.

The process of MVB maturation and trafficking is complex and involves multiple protein factors that regulate membrane dynamics and cargo sorting. Once the MVBs reach a certain stage of development, they can either fuse with lysosomes for degradation or fuse with the plasma membrane. Fusion with the plasma membrane is the crucial step in exosome release, where the ILVs are expelled from the cell into the extracellular environment as exosomes. This secreted cargo within exosomes can include proteins, lipids, messenger RNAs (mRNAs), and microRNAs (miRNAs), which can then influence the function of recipient cells. The study of exosomenbildung is important for understanding intercellular communication and has implications for disease diagnosis and therapeutic development.