Differential requirement of Tyr1062 multidocking site by RET isoforms to promote neural cell scattering and epithelial cell branching.
The receptor tyrosine kinase RET is alternatively spliced to yield two main isoforms, RET9 and RET51, which differ in their carboxyl terminal. Activated RET induces different biological responses such as morphological transformation, neurite outgrowth, proliferation, cell migration and branching. The two isoforms have been suggested to have separate intracellular signaling pathways and different roles in mouse development. Here we show that both isoforms are able to induce cell scattering of SK-N-MC neuroepithelioma cell line and branching tubule formation in MDCK cell line. However, the Y1062F mutation, which abrogates the transforming activity of both activated RET isoforms in NIH3T3 cells, does not abolish scattering and branching morphogenesis of RET51, whereas impairs these biological effects of RET9. The GDNF-induced biological effects of RET51 are inhibited by the simultaneous abrogation of both Tyr1062 and Tyr1096 docking sites. Thus, Tyr1096 may substitute the functions of Tyr1062. GRB2 is the only known adaptor protein binding to Tyr1096. Dominant-negative GRB2 expressed in MDCK cells together with RET9 or RET51 significantly reduces branching. Therefore, GRB2 is necessary for RET-mediated branching of MDCK cells.
Department of Experimental Oncology, Research Unit #3, Istituto Nazionale Tumori, Via G. Venezian, 1 20133 Milan, Italy.
Debora
D
Degl'Innocenti
Elena
E
Arighi
Anna
A
Popsueva
Romina
R
Sangregorio
Luisella
L
Alberti
Maria Grazia
MG
Rizzetti
Cristina
C
Ferrario
Hannu
H
Sariola
Marco A
MA
Pierotti
Maria Grazia
MG
Borrello
D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D003001:Cloning, Molecular; D017931:DNA Primers; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D051380:GRB2 Adaptor Protein; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007668:Kidney; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009414:Nerve Growth Factors / Q000494:pharmacology; D016501:Neurites / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014443:Tyrosine; D048051:p38 Mitogen-Activated Protein Kinases
D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; D051380:GRB2 Adaptor Protein; C495040:Gdnf protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; C495949:Grb2 protein, mouse; D009414:Nerve Growth Factors; D015513:Oncogene Proteins; D020033:Protein Isoforms; D011506:Proteins; D011993:Recombinant Fusion Proteins; D014443:Tyrosine; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D020794:Receptor Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases