Isolation and characterization of a secreted, cell-surface glycoprotein SCUBE2 from humans

Ming Tzu Tsai, Chien Jui Cheng, Yuh Charn Lin, Chun Chuan Chen, Ann Ru Wu, Min Tzu Wu, Cheng Chin Hsu, Ruey Bing Yang

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)


SCUBE2 [signal peptide, CUB domain, EGF (epidermal growth factor)-like protein 2] belongs to an evolutionarily conserved SCUBE protein family, which possesses domain organization characteristic of an N-terminal signal peptide sequence followed by nine EGF-like repeats, a spacer region, three cysteine-rich repeat motifs, and one CUB domain at the C-terminus. Despite several genetic analyses suggesting that the zebrafish orthologue of the mammalian SCUBE2 gene participates in HH (Hedgehog) signalling, the complete full-length cDNA and biochemical function for mammalian SCUBE2 on HH signalling remains uninvestigated. In the present study, we isolated the full-length cDNA and studied the role of human SCUBE2 in the HH signalling cascade. When overexpressed, recombinant human SCUBE2 manifests as a secreted surface-anchored glycoprotein. Deletion mapping analysis defines the critical role of the spacer region and/or cysteine-rich repeats for membrane association. Further biochemical analyses and functional reporter assays demonstrated that human SCUBE2 can specifically interact with SHH (Sonic Hedgehog) and SHH receptor PTCH1 (Patched-1), and enhance the SHH signalling activity within the cholesterolrich raft microdomains of the plasma membranes. Together, our results reveal that human SCUBE2 is a novel positive component of the HH signal, acting upstream of ligand binding at the plasma membrane. Thus human SCUBE2 could play important roles in HH-related biology and pathology, such as during organ development and tumour progression.

Original languageEnglish
Pages (from-to)119-128
Number of pages10
JournalBiochemical Journal
Issue number1
Publication statusPublished - Aug 15 2009


  • CUB domain
  • Cell-surface protein
  • Epidermal growth factor-like repeat (EGF-like repeat)
  • Glycoprotein
  • Signal transduction
  • Sonic Hedgehog

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Cell Biology


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