Amino-terminal processing of cell surface heparin-binding epidermal growth factor-like growth factor up-regulates its juxtacrine but not its paracrine growth factor activity.
Human heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) expressed on Chinese hamster ovary (CHO) cells is synthesized as a 19-kDa major, and 22- and 27-kDa minor, membrane-anchored precursors (proHB-EGF). In contrast, the 27-kDa species is major and the 19- and 22-kDa ones are minor in mouse proHB-EGF. The juxtacrine growth factor activities of human and mouse proHB-EGFs on CHO cells toward EP170.7 cells in co-culture are significantly different. To investigate the relationship between the juxtacrine growth factor activities and the molecular species, we prepared human-mouse chimeras. Chimeras that have the human amino-terminal sequence with a mouse EGF-like domain showed approximately 8-fold up-regulation of the juxtacrine growth factor activity and the predominance of a 19-22-kDa major species. In contrast, chimeras that have the mouse amino-terminal sequence with a human EGF-like domain showed approximately 5-fold down-regulation of the juxtacrine activity and the predominance of the 27-kDa major species. A Gly32.HB-EGF (117-amino acid form), which is amino-terminally extended, induced the same mitogenic activity as that of Arg73.HB-EGF (75-amino acid form), which is amino-terminally truncated. These results strongly suggested that amino-terminal processing of human proHB-EGF would be required for up-regulation of its juxtacrine growth factor activity, but not for its paracrine activity.
Nakagawa
T
T
Department of Biochemistry, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565, Japan.
Higashiyama
S
S
Mitamura
T
T
Mekada
E
E
Taniguchi
N
N
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D016466:CHO Cells; D002455:Cell Division; D006224:Cricetinae; D004815:Epidermal Growth Factor / Q000737:chemistry; D045683:Furin; D006133:Growth Substances / Q000737:chemistry / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D013329:Structure-Activity Relationship; D013381:Subtilisins / Q000378:metabolism; D060245:Tetraspanin 29
D015703:Antigens, CD; C554869:CD9 protein, human; C554870:Cd9 protein, mouse; D006133:Growth Substances; C587883:HBEGF protein, human; C587884:Hbegf protein, mouse; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D060245:Tetraspanin 29; D004815:Epidermal Growth Factor; D013381:Subtilisins; D045683:Furin