Targeting independent of protein glycosylation

Secretory proteins and plasma membrane proteins do not need an oligosaccharide signal for proper localization. Other types of signaling are assumed (protein conformation, a certain three-dimensional motif in its structure). These proteins can somehow be "sent" to the apical or basolateral part of the plasma membrane, or they are sorted for a dual type of secretion: constitutive secretion which is continuous and rapid, the proteins do not condense in secretory vesicles, or directed secretion, where proteins are stored and concentrated in vesicles and released from the cell upon hormonal stimulation. Only then do the vesicles fuse with the cytoplasmic membrane and their contents are released outside the cell. An example of controlled secretion is the release of digestive enzymes from the acinar cells of the pancreas or the release of peptide hormones from endocrine cells.

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