Ubiquitin ligase Nedd4L targets activated Smad2/3 to limit TGF-beta signaling.
TGF-beta induces phosphorylation of the transcription factors Smad2 and Smad3 at the C terminus as well as at an interdomain linker region. TGF-beta-induced linker phosphorylation marks the activated Smad proteins for proteasome-mediated destruction. Here, we identify Nedd4L as the ubiquitin ligase responsible for this step. Through its WW domain, Nedd4L specifically recognizes a TGF-beta-induced phosphoThr-ProTyr motif in the linker region, resulting in Smad2/3 polyubiquitination and degradation. Nedd4L is not interchangeable with Smurf1, a ubiquitin ligase that targets BMP-activated, linker-phosphorylated Smad1. Nedd4L limits the half-life of TGF-beta-activated Smads and restricts the amplitude and duration of TGF-beta gene responses, and in mouse embryonic stem cells, it limits the induction of mesoendodermal fates by Smad2/3-activating factors. Hierarchical regulation is provided by SGK1, which phosphorylates Nedd4L to prevent binding of Smad2/3. Previously identified as a regulator of renal sodium channels, Nedd4L is shown here to play a broader role as a general modulator of Smad turnover during TGF-beta signal transduction.
Gao
Sheng
S
Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
Alarcón
Claudio
C
Sapkota
Gopal
G
Rahman
Sadia
S
Chen
Pan-Yu
PY
Goerner
Nina
N
Macias
Maria J
MJ
Erdjument-Bromage
Hediye
H
Tempst
Paul
P
Massagué
Joan
J
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D051379:Mice; D008969:Molecular Sequence Data; D000075702:Nedd4 Ubiquitin Protein Ligases; D010766:Phosphorylation / Q000187:drug effects; D025821:Polyubiquitin / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D051899:Smad2 Protein / Q000235:genetics / Q000378:metabolism*; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D000099184:Serum-Glucocorticoid Regulated Kinases
D056827:Endosomal Sorting Complexes Required for Transport; D017874:Immediate-Early Proteins; D000075702:Nedd4 Ubiquitin Protein Ligases; D025821:Polyubiquitin; D017346:Protein Serine-Threonine Kinases; D051899:Smad2 Protein; D051900:Smad3 Protein; D016212:Transforming Growth Factor beta; D044767:Ubiquitin-Protein Ligases; D000099184:Serum-Glucocorticoid Regulated Kinases; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; C000618485:Nedd4L protein, human; C000618461:Nedd4l protein, mouse; C498342:SMURF1 protein, human