Characterization of latent recombinant TGF-β2 produced by chinese hamster ovary cells

✍ Scribed by Mario N. Lioubin; Linda Madisen; Hans Marquardt; Richard Roth; Kristina S. Kovacina; A. F. Purchio

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 864 KB
• Volume: 45
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240450118

✦ Synopsis

Latent recombinant transforming growth factor-P2 (LrTGF-P2) complex has been purified from serumfree media conditioned by Chinese hamster ovary cells transfected with a plasmid encoding the precursor. Under neutral conditions, LrTGF-02 had an apparent molecular weight of 130 kDa. The complex contained both mature and pro-region sequences. Acidification of LrTGF-P2 resulted in the release of mature 24 kDa TGF-P2 from the high molecular weight pro-region-containing complex, suggesting that TGF-P2 was non-covalently associated with this complex. These results were confirmed by crosslinking experiments performed on partially purified LrTGF-P2. Protein sequence analysis of the purified TGF-P2 pro-region indicated that signal peptide cleavage occurred between ser(20) and Ieu( 21). The pro-region, which previously was found to contain mannose-6-phosphate, bound to the mannose-6-phosphate receptor. Proteolytic cleavage of mature TGF-P2 from pro-TGF-P2 was inhibited by monensin and chloroquin suggesting that binding to this receptor and subsequent transport to acidic vesicles may be involved in the processing of rTGF-P2 precursor.