The pro-region of the yeast prepro-alpha-factor is essential for membrane translocation of human insulin-like growth factor 1 in vivo.
Four yeast secretion signals, the 19-amino-acid invertase signal sequence, the 17-amino-acid acid-phosphatase signal sequence, and the pre-sequence and prepro-sequence of prepro-alpha-factor have been used to look for the secretion of recombinant human insulin-like growth factor 1 (IGF1) from Saccharomyces cerevisiae. Only the prepro-sequence, often referred to as the alpha-factor leader and consisting of an N-terminal 19-amino-acid pre-sequence or signal sequence attached to a 66-amino-acid pro-region, permits secretion of IGF1. The signal sequences alone do not allow the translocation of IGF1 into the endoplasmic reticulum. This is evident from the fact that IGF1-like molecules, to which the signal sequences are still attached, accumulate intracellularly in the cytosol. Fusion of the pro-region of the alpha-factor leader to the C-terminus of the acid-phosphatase and invertase signal sequences allows IGF1 to be secreted once again. These results reveal the essential role of the pro-region of the alpha-factor leader in the secretion of IGF1 and indicate that it may have a function in guiding a nascent IGF1 polypeptide to a state in which translocation can occur.
Chaudhuri
B
B
Biotechnology Department, Ciba-Geigy Ltd., Basel, Switzerland.
Steube
K
K
Stephan
C
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007163:Immunosorbent Techniques; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D014162:Transfection
D005656:Fungal Proteins; C048632:MF(ALPHA)1 protein, S cerevisiae; D011498:Protein Precursors; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D007334:Insulin-Like Growth Factor I