A novel Kex2 enzyme can process the proregion of the yeast alpha-factor leader in the endoplasmic reticulum instead of in the Golgi.
The prepro sequence of the yeast prepro-alpha-factor, usually referred to as the alpha-factor leader, has often been used for the efficient secretion of heterologous proteins from the yeast Saccharomyces cerevisiae. The alpha-factor leader consists of a 19-amino acid N-terminal pre or signal sequence followed by a 66-amino acid proregion. After removal of the signal sequence during membrane translocation, the proregion is cleaved from the precursor protein by the Kex2 endoprotease only in a late Golgi compartment. Here we report that a modified Kex2 enzyme, containing at the C-terminus the HDEL tetrapeptide, cleaves the proregion from the alpha-factor leader--human insulin like growth factor-1 fusion protein in the endoplasmic reticulum. The processing of pro-proteins earlier in the secretion pathway could be helpful in defining the cellular function of the proregions present naturally in various eucaryotic precursor proteins.
Chaudhuri
B
B
Department of Biotechnology, Ciba-Geigy Ltd., Basel, Switzerland.
Latham
S E
SE
Helliwell
S B
SB
Seeboth
P
P
D001483:Base Sequence; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D043484:Proprotein Convertases; D011498:Protein Precursors / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism; D013381:Subtilisins
D005656:Fungal Proteins; C048632:MF(ALPHA)1 protein, S cerevisiae; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D013002:Somatomedins; D043484:Proprotein Convertases; D012697:Serine Endopeptidases; D013381:Subtilisins; C058751:KEX2 protein, S cerevisiae