ATPase activity of a yeast secretory glycoprotein allows ER exit during inactivation of COPII components Sec24p and Sec13p.

Proteins exit the endoplasmic reticulum (ER) in vesicles pinching off from the membrane at sites covered by the COPII coat, which consists of Sec23/24p and Sec13/31p. We have shown that the glycoprotein Hsp150 exits the ER in the absence of Sec13p or any member of the Sec24p family. The determinant responsible for this resides in the C-terminal domain of Hsp150 (CTD).

Unassisted translocation of large polypeptide domains across phospholipid bilayers.

Although transmembrane proteins generally require membrane-embedded machinery for integration, a few can insert spontaneously into liposomes. Previously, we established that the tail-anchored (TA) protein cytochrome b(5) (b5) can posttranslationally translocate 28 residues downstream to its transmembrane domain (TMD) across protein-free bilayers (Brambillasca, S., M.

Regulation and recovery of functions of Saccharomyces cerevisiae chaperone BiP/Kar2p after thermal insult.

We described earlier a novel mode of regulation of Hsp104, a cytosolic chaperone directly involved in the refolding of heat-denatured proteins, and designated it delayed upregulation, or DUR. When Saccharomyces cerevisiae cells grown at the physiological temperature of 24 degrees C, preconditioned at 37 degrees C, and treated briefly at 50 degrees C were shifted back to 24 degrees C, Hsp104 expression was strongly induced after 2.5 h of recovery and returned back to normal after 5 h.

Production of heterologous proteins in yeast with the aid of the Hsp150delta carrier.

Proper folding, and consequently exit from the endoplasmic reticulum (ER) and secretion of heterologous exocytic proteins in yeast can be rescued by fusing the proteins to certain yeast-derived polypeptides. Biologically active mammalian glycoproteins can be produced in Saccharomyces cerevisiae and Pichia pastoris by joining them to a fragment of a natural secretory glycoprotein of S. cerevisiae, Hsp150delta.