PUBLICATION

Electrostatics and N-glycan-mediated membrane tethering of SCUBE1 is critical for promoting bone morphogenetic protein signalling

Authors
Liao, W.J., Tsao, K.C., Yang, R.B.
ID
ZDB-PUB-151225-9
Date
2016
Source
The Biochemical journal   473(5): 661-72 (Journal)
Registered Authors
Yang, Ruey-Bing (Ray)
Keywords
bone morphogenetic protein, electrostatic interaction, N-glycosylation, peripheral membrane protein, SCUBE1, signalling
MeSH Terms
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Bone Morphogenetic Proteins/metabolism*
  • Cell Membrane/metabolism
  • Glycosylation
  • HEK293 Cells
  • Hematopoiesis
  • Humans
  • Membrane Microdomains/metabolism
  • Membrane Proteins/genetics
  • Membrane Proteins/metabolism*
  • Molecular Sequence Data
  • Mutation
  • Oligosaccharides/metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Signal Transduction
  • Static Electricity
  • Zebrafish/blood
PubMed
26699903 Full text @ Biochem. J.
Abstract
SCUBE1, a secreted and membrane-bound glycoprotein, has a modular protein structure composed of an NH2-terminal signal peptide sequence followed by 9 epidermal growth factor (EGF)-like repeats, a spacer region and 3 cysteine-rich (CR) motifs with multiple potential N-linked glycosylation sites, and one CUB domain at the COOH terminus. Soluble SCUBE1 is a biomarker of platelet activation but an active participant of thrombosis via its adhesive EGF-like repeats, whereas its membrane-associated form acts as a bone morphogenetic protein (BMP) co-receptor in promoting BMP signal activity. However, the mechanism responsible for the membrane tethering and biological importance of N-glycosylation of SCUBE1 remains largely unknown. In this study, molecular mapping analysis identified a polycationic segment (amino acids 501-550) in the spacer region required for its membrane tethering via electrostatic interactions possibly with the anionic heparan sulfate proteoglycans. Furthermore, deglycosylation by peptide-N-glycosidase F treatment revealed that N-glycans within the CR motif are essential for membrane recruitment through lectin-mediated surface retention. Injection of mRNA encoding zebrafish wild-type but not N-glycan-deficient scube1 restores the expression of hematopoietic and erythroid markers ( scl and gata1 ) in scube1 -knockdown embryos. We describe novel mechanisms in targeting SCUBE1 to the plasma membrane and demonstrate that N-glycans are required for SCUBE1 functions during primitive hematopoiesis in zebrafish.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping