Regulation of Sufu activity by p66β and Mycbp provides new insight into vertebrate Hedgehog signaling.
Control of Gli function by Suppressor of Fused (Sufu), a major negative regulator, is a key step in mammalian Hedgehog (Hh) signaling, but how this is achieved in the nucleus is unknown. We found that Hh signaling results in reduced Sufu protein levels and Sufu dissociation from Gli proteins in the nucleus, highlighting critical functions of Sufu in the nucleus. Through a proteomic approach, we identified several Sufu-interacting proteins, including p66β (a member of the NuRD [nucleosome remodeling and histone deacetylase] repressor complex) and Mycbp (a Myc-binding protein). p66β negatively and Mycbp positively regulate Hh signaling in cell-based assays and zebrafish. They function downstream from the membrane receptors, Patched and Smoothened, and the primary cilium. Sufu, p66β, Mycbp, and Gli are also detected on the promoters of Hh targets in a dynamic manner. Our results support a new model of Hh signaling in the nucleus. Sufu recruits p66β to block Gli-mediated Hh target gene expression. Meanwhile, Mycbp forms a complex with Gli and Sufu without Hh stimulation but remains inactive. Hh pathway activation leads to dissociation of Sufu/p66β from Gli, enabling Mycbp to promote Gli protein activity and Hh target gene expression. These studies provide novel insight into how Sufu controls Hh signaling in the nucleus.
Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA;
Chuwen
C
Lin
Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA;
Erica
E
Yao
Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA;
Kevin
K
Wang
Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA;
Yoko
Y
Nozawa
Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA;
Hirohito
H
Shimizu
Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158.
Jeffrey R
JR
Johnson
Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA;
Jau-Nian
JN
Chen
Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158.
Nevan J
NJ
Krogan
Cardiovascular Research Institute, University of California at San Francisco, San Francisco, California 94158, USA; pao-tien.chuang@ucsf.edu.
Pao-Tien
PT
Chuang
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D053823:Hedgehog Proteins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009154:Mutation; D041681:NIH 3T3 Cells; D011485:Protein Binding; D040901:Proteomics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D055291:Salivary alpha-Amylases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015027:Zebrafish / Q000235:genetics; D000071676:Zinc Finger Protein GLI1
C498520:Gli1 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D012097:Repressor Proteins; C490763:Sufu protein, mouse; D000071676:Zinc Finger Protein GLI1; C524799:Amy1 protein, mouse; D055291:Salivary alpha-Amylases
Gli; Hh signaling; Mycbp; Sufu; p66β