Two pathways of exocytosis newly synthesized membrane lipids CONSTITUTIVE SECRETION membrane plasma membrane newly synthesized plasma membrane protein CYTOSOL signal such as trans 一+hmm ne or transduction REGULAT ③ SECRET regulated omron olgi apparatus storing secretory o Constitutive exocytosis pathway - Many soluble proteins are continually secreted from the cell by the constitutive secretory pathway Regulated exocytosis pathway - Selected proteins in the trans Golg network are diverted into secretory vesicles, where the proteins are concentrated and stored until an extracellular signal stimulates their secretionTwo pathways of exocytosis •Constitutive exocytosis pathway -- Many soluble proteins are continually secreted from the cell by the constitutive secretory pathway •Regulated exocytosis pathway -- Selected proteins in the trans Golgi network are diverted into secretory vesicles, where the proteins are concentrated and stored until an extracellular signal stimulates their secretion