Notch oncoproteins depend on gamma-secretase/presenilin activity for processing and function.
During normal development Notch receptor signaling is important in regulating numerous cell fate decisions. Mutations that truncate the extracellular domain of Notch receptors can cause aberrant signaling and promote unregulated cell growth. We have examined two types of truncated Notch oncoproteins that arise from proviral insertion into the Notch4 gene (Notch4/int-3) or a chromosomal translocation involving the Notch1 gene (TAN-1). Both Notch4/int-3 and TAN-1 oncoproteins lack most or all of their ectodomain. Normal Notch signaling requires gamma-secretase/presenilin-mediated proteolytic processing, but whether Notch oncoproteins are also dependent on gamma-secretase/presenilin activity is not known. We demonstrate that Notch4/int-3-induced activation of the downstream transcription factor, CSL, is abrogated in cells deficient in presenilins or treated with a pharmacological inhibitor of gamma-secretase/presenilins. Furthermore, we find that both Notch4/int-3 and TAN-1 accumulate at the cell surface, where presenilin-dependent cleavage occurs, when gamma-secretase/presenilin activity is inhibited. gamma-Secretase/presenilin inhibition effectively blocks cellular responses to Notch4/int-3, but not TAN-1, apparently because some TAN-1 polypeptides lack transmembrane domains and do not require gamma-secretase/presenilin activity for nuclear access. These studies highlight potential uses and limitations of gamma-secretase/presenilin inhibitors in targeted therapy of Notch-related neoplasms.
Das
Indranil
I
Department of Pathology and Obstetrics/Gynecology, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA.
Craig
Colleen
C
Funahashi
Yasuhiro
Y
Jung
Kwang-Mook
KM
Kim
Tae-Wan
TW
Byers
Richard
R
Weng
Andrew P
AP
Kutok
Jeffery L
JL
Aster
Jon C
JC
Kitajewski
Jan
J
D000256:Adenoviridae / Q000235:genetics; D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D019921:Biotinylation; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D010450:Endopeptidases / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008954:Models, Biological; D053764:Presenilin-1; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051881:Receptor, Notch1; D051883:Receptor, Notch2; D000074562:Receptor, Notch4; D011956:Receptors, Cell Surface / Q000378:metabolism; D051880:Receptors, Notch; D015398:Signal Transduction; D014157:Transcription Factors; D014162:Transfection; D014471:Umbilical Veins / Q000166:cytology
D008024:Ligands; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; C497764:NOTCH2 protein, human; C106075:NOTCH4 protein, human; C497762:Notch1 protein, mouse; C497765:Notch2 protein, mouse; C508853:PSEN1 protein, human; D053764:Presenilin-1; D011518:Proto-Oncogene Proteins; D051881:Receptor, Notch1; D051883:Receptor, Notch2; D000074562:Receptor, Notch4; D011956:Receptors, Cell Surface; D051880:Receptors, Notch; D014157:Transcription Factors; D008156:Luciferases; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse