After leaving the Golgi apparatus, proteins following the constitutive secretion pathway merge with the cell membrane and release their cargo by a process called exocytosis. Clicking
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Upon reaching the cell membrane, the secretory vesicles from the Golgi merge with the plasma membrane of the cell by a process called exocytosis. The cargo proteins they contain are then released into the extracellular matrix, and the lipids and membrane of the vesicles are donated to the plasma membrane.
Certain white blood cells use the constitutive pathway to secrete interleukins, a kind of signaling protein used for intercellular communication between other white blood cells. Interleukins play an important role in the proper function of the immune system.
Other cells, such as fibroblasts, constitutively secrete proteins such as collagen and proteoglycans and help to maintain the structural integrity of connective tissue.