Sorting and processing of secretory proteins

Sorting and processing of secretory proteins.

a common biosynthetic origin in the rough endoplasmic reticulum (RER), from where they are transported to the Golgi complex. It is in the trans-Golgi network (TGN) that proteins destined for the regulated secretory pathway will be sorted from those to be secreted via the constitutive pathway. Both of these pathways involve vesicular transfer to the plasma membrane followed by the secretory even...

Culture patterns and sorting of rat Sertoli cell secretory proteins.

A cocultivation chamber and two types of permeable substrates have been used to study: (1) the culture patterns of rat Sertoli and peritubular cells, and Sertoli cells cocultured with spermatogenic cells or peritubular cells; and (2) the polarized secretion of Sertoli cell-specific proteins transferrin, S70 and S45-S35 heterodimeric protein. Substrates included a nylon mesh (with openings of 10...

Concentrative sorting of secretory cargo proteins into COPII-coated vesicles

Here, we show that efficient transport of membrane and secretory proteins from the ER of Saccharomyces cerevisiae requires concentrative and signal-mediated sorting. Three independent markers of bulk flow transport out of the ER indicate that in the absence of an ER export signal, molecules are inefficiently captured into coat protein complex II (COPII)-coated vesicles. A soluble secretory prot...

Sorting of three secretory proteins to distinct secretory granules in acidophilic cells of cow anterior pituitary

The distribution of three proteins discharged by regulated exocytosis--growth hormone (GH), prolactin (PRL), and secretogranin II (SgII)--was investigated by double immunolabeling of ultrathin frozen sections in the acidophilic cells of the bovine pituitary. In mammotrophs, heavy PRL labeling was observed over secretory granule matrices (including the immature matrices at the trans Golgi surfac...

Glycosylation and Sorting of Secretory Proteins in the Endoplasmic Reticulum of the Yeast Saccharomyces cerevisiae