Furin-, ADAM 10-, and gamma-secretase-mediated cleavage of a receptor tyrosine phosphatase and regulation of beta-catenin's transcriptional activity.
Several receptor protein tyrosine phosphatases (RPTPs) are cell adhesion molecules involved in homophilic interactions, suggesting that RPTP outside-in signaling is coupled to cell contact formation. However, little is known about the mechanisms by which cell density regulates RPTP function. We show that the MAM family prototype RPTPkappa is cleaved by three proteases: furin, ADAM 10, and gamma-secretase. Cell density promotes ADAM 10-mediated cleavage and shedding of RPTPkappa. This is followed by gamma-secretase-dependent intramembrane proteolysis of the remaining transmembrane part to release the phosphatase intracellular portion (PIC) from the membrane, thereby allowing its translocation to the nucleus. When cells were treated with leptomycin B, a nuclear export inhibitor, PIC accumulated in nuclear bodies. PIC is an active protein tyrosine phosphatase that binds to and dephosphorylates beta-catenin, an RPTPkappa substrate. The expression of RPTPkappa suppresses beta-catenin's transcriptional activity, whereas the expression of PIC increases it. Notably, this increase required the phosphatase activity of PIC. Thus, both isoforms have acquired opposing roles in the regulation of beta-catenin signaling. We also found that RPTPmu, another MAM family member, undergoes gamma-secretase-dependent processing. Our results identify intramembrane proteolysis as a regulatory switch in RPTPkappa signaling and implicate PIC in the activation of beta-catenin-mediated transcription.
Anders
Lars
L
Department of Molecular Biology, Max Planck Institute of Biochemistry, Martinsried, Germany. lars_anders@dfci.harvard.edu
Mertins
Philipp
P
Lammich
Sven
S
Murgia
Marta
M
Hartmann
Dieter
D
Saftig
Paul
P
Haass
Christian
C
Ullrich
Axel
A
D051722:ADAM Proteins / Q000378:metabolism*; D000072197:ADAM10 Protein; D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D019921:Biotinylation; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D019556:COS Cells; D002277:Carcinoma / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003720:Densitometry; D004305:Dose-Response Relationship, Drug; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D045683:Furin / Q000378:metabolism*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D045325:HCT116 Cells; D006801:Humans; D007700:Kinetics; D007976:Leupeptins / Q000494:pharmacology; D008156:Luciferases / Q000032:analysis / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D041681:NIH 3T3 Cells; D010957:Plasmids / Q000235:genetics; D011233:Precipitin Tests; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D034622:RNA Interference; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D014158:Transcription, Genetic; D014268:Trifluoperazine / Q000494:pharmacology; D051176:beta Catenin / Q000235:genetics*
D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D008565:Membrane Proteins; D051176:beta Catenin; D049452:Green Fluorescent Proteins; D014268:Trifluoperazine; D008156:Luciferases; C516859:PTPRM protein, human; D017027:Protein Tyrosine Phosphatases; C516860:Ptprm protein, mouse; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D045683:Furin; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491236:ADAM10 protein, human; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde