The epidermal growth factor receptor as a substrate for a kinase-splitting membranal proteinase.
A brush-border membranal proteinase, which specifically clips the catalytic subunit of cAMP-dependent protein kinase, is shown to cleave the receptor for the epidermal growth factor (EGF) (Mr = 170,000) into two fragments of Mr = 140,000 and 30,000. The 140-kDa fragment retains its EGF-binding site and its EGF-dependent protein tyrosine kinase activity on exogenous substrates, but it loses its capacity to undergo self-phosphorylation. It is shown to be distinct from the 150-kDa fragment of the EGF receptor obtained by the Ca2+-activated neutral proteinase. The membranal proteinase strictly recognizes the native structure of the receptor and fails to cleave either the denatured receptor or its 150-kDa degradation product. Thus the membranal proteinase acts as a conformation-recognizing probe for both the protein-tyrosine kinase domain of the EGF receptor and the catalytic subunit of cAMP-dependent protein-Ser/Thr kinase, suggesting that the known sequence homology between these two kinases is also reflected in their conformation. The well defined 140-kDa fragment described here is useful for structure-function studies of the EGF receptor.
Seger
R
R
Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
Yarden
Y
Y
Kashles
O
O
Goldblatt
D
D
Schlessinger
J
J
Shaltiel
S
S
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D000242:Cyclic AMP / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008871:Microvilli / Q000201:enzymology; D008970:Molecular Weight; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D011487:Protein Conformation; D011489:Protein Denaturation; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D013379:Substrate Specificity
D009842:Oligopeptides; D010446:Peptide Fragments; D011480:Protease Inhibitors; D000255:Adenosine Triphosphate; C002101:chymostatin; D004492:Edetic Acid; D000242:Cyclic AMP; D011494:Protein Kinases; D066246:ErbB Receptors; D010450:Endopeptidases