Title : C-mannosylation and O-fucosylation of the
thrombospondin type 1 module
Abstract :
- Thrombospondin-1 ( TSP-1 ) is a multidomain protein that has been implicated in cell adhesion, motility, and growth
- Some of these functions have been localized to the three thrombospondin type 1 repeats (TSRs), modules of approximately 60 amino acids in length with conserved Cys and Trp residues
- The Trp residues occur in WXXW patterns, which are the recognition motifs for protein C-mannosylation
- This modification involves the attachment of an alpha-mannosyl residue to the C-2 atom of the first tryptophan
- Analysis of human platelet TSP-1 revealed that Trp-368, -420, -423, and -480 are C-mannosylated
- Mannosylation also occurred in recombinant, baculovirally expressed TSR modules from Sf9 and "High Five" cells, contradictory to earlier reports that such cells do not carry out this reaction
- In the course of these studies it was appreciated that the TSRs in TSP-1 undergo a second form of unusual glycosylation
- By using a novel mass spectrometric approach, it was found that Ser-377, Thr-432, and Thr-489 in the motif CSX (S/T)CG carry the O-linked disaccharide Glc-Fuc-O-Ser/Thr
- This is the first protein in which such a disaccharide has been identified, although protein O-fucosylation is well described in epidermal growth factor-like modules
- Both C- and O-glycosylations take place on residues that have been implicated in the interaction of TSP-1 with glycosaminoglycans or other cellular receptors
Output (sent_index, trigger,
protein,
sugar,
site):
- 5. C-mannosylated, , -, -, Trp-368, -420, -423, and -480
- 8. carry, , -, the O-linked disaccharide, Ser-377, Thr-432, and Thr-489
Output(Part-Of) (sent_index,
protein,
site):
- 8. CG, Ser-377, Thr-432, and Thr-489
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):
- 5. thrombospondin type 1, -, Trp-368, -420, -423, and -480
- 8. CG, the O-linked disaccharide, Ser-377, Thr-432, and Thr-489