ErbB2 and ErbB4 Cbl binding sites can functionally replace the ErbB1 Cbl binding site.
Poor downregulation of ErbB receptors is associated with enhanced downstream signaling and tumorigenesis. It has been suggested that poor downregulation of ErbB-2, -3 and -4 receptors when compared to ErbB1 is due to decreased recruitment of Cbl E3 ligase proteins. However, a highly conserved Cbl binding site is not only present in ErbB1/EGFR (FLQRpY(1045)SSDP), but also in ErbB2 (PLQRpY(1091)SEDP) and ErbB4 (STQRpY(1103)SADP). We therefore replaced the ErbB1 Cbl binding site by that of ErbB2 and ErbB4. Whereas retrovirally infected NIH3T3 cells containing the EGFR Y1045F mutation showed dramatically impaired Cbl recruitment, EGFR ubiquitination and delayed EGFR degradation, replacement of the EGFR Cbl binding site by that of ErbB2 or ErbB4 did not affect Cbl recruitment, receptor-ubiquitination, -degradation, -downregulation or ligand degradation. We conclude that poor downregulation of ErbB2 and ErbB4 receptors is not due to sequence variations in the Cbl binding site of these receptors.
Jansen
Suzanne M
SM
Department of Cell Biology, Faculty of Science, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Sleumer
Laura S
LS
Damen
Ester
E
Meijer
Inez M J
IM
van Zoelen
Everardus J J
EJ
van Leeuwen
Jeroen E M
JE
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D015536:Down-Regulation; D011992:Endosomes / Q000201:enzymology; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D050721:Proto-Oncogene Proteins c-cbl / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D066247:Receptor, ErbB-4; D015398:Signal Transduction; D054875:Ubiquitination
D066246:ErbB Receptors; D050721:Proto-Oncogene Proteins c-cbl; D018719:Erb-b2 Receptor Tyrosine Kinases; D066247:Receptor, ErbB-4; C587689:ERBB4 protein, human; C587690:Erbb4 protein, mouse