Different transforming growth factor-alpha species are derived from a glycosylated and palmitoylated transmembrane precursor.
cDNA analysis has revealed that the 50 amino acid transforming growth factor-alpha (TGF-alpha) is derived from a 160 amino acid precursor. Antibodies to TGF-alpha and to a C-terminal portion of the precursor were used to study the biosynthesis and processing of the precursor. CHO cells transfected with a TGF-alpha expression vector secrete high levels of TGF-alpha; a mixture of species of about 18 kd is secreted in addition to the 50 amino acid form. These larger species are N-glycosylated and are derived from the same precursor as the smaller form. The C-terminal segment of the precursor remains anchored in the membrane and has covalently attached palmitate. The newly synthesized TGF-alpha precursor is thus a transmembrane protein that subsequently undergoes external proteolytic cleavages, releasing several TGF-alpha species.
Bringman
T S
TS
Lindquist
P B
PB
Derynck
R
R
D000818:Animals; D000906:Antibodies; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D006031:Glycosylation; D008565:Membrane Proteins / Q000378:metabolism*; D010168:Palmitates / Q000378:metabolism; D010455:Peptides / Q000276:immunology / Q000378:metabolism*; D011498:Protein Precursors / Q000276:immunology / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D015291:Transforming Growth Factors
D000906:Antibodies; D008565:Membrane Proteins; D010168:Palmitates; D010455:Peptides; D011498:Protein Precursors; D015291:Transforming Growth Factors