Constitutive and basal secretion from the endocrine cell line, AtT-20

The HYA.15.6 variant exhibited multiple defects, including the loss of secretory granules with an electron-dense core, and the loss of several granule content proteins, ACTH, sulfated proteins (B15), and granule-specific sulfated proteoglycans. The variant could reflect an early developmental state before the expression of the secretory granule content proteins is switched on, assuming that expression of granule contents is required for dense core secretory granule formation. We cannot determine whether, in the absence of dense core formation, empty secretory granule membranes still form, but if they do they are not capable of storing and releasing on stimulation the exocrine protein trypsinogen.