Cellular component - Golgi apparatus
The Golgi apparatus is a series of flattened, cisternal membranes and similar vesicles usually arranged in close apposition to each other to form stacks. In mammalian cells, the Golgi apparatus is juxtanuclear, often pericentriolar. The stacks are connected laterally by tubules to create a perinuclear ribbon structure, the 'Golgi ribbon'. In plants and lower animal cells, the Golgi exists as many copies of discrete stacks dispersed throughout the cytoplasm. The Golgi is a polarized structure with, in most higher eukaryotic cells, a cis-face associated with a tubular reticular network of membranes facing the endoplasmic reticulum, the cis-Golgi network (CGN), a medial area of disk-shaped flattened cisternae, and a trans-face associated with another tubular reticular membrane network, the trans-Golgi network (TGN) directed toward the plasma membrane and compartments of the endocytic pathway. The Golgi apparatus receives the entire output of de novo synthesized polypeptides from the ER, and functions to posttranslationally process and sort them within vesicles destined to their proper final destination (e.g. plasma membrane, endosomes, lysosomes).
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