Title : Identification and characterization of
asporin
Abstract :
- a novel member of the leucine-rich repeat protein family leucine-rich repeat protein family closely related to decorin and biglycan
- Asporin , a novel member of the leucine-rich repeat family leucine-rich repeat family of proteins, was partially purified from human articular cartilage and meniscus
- Cloning of human and mouse asporin cDNAs revealed that the protein is closely related to decorin and biglycan
- It contains a putative propeptide , 4 amino-terminal cysteines , 10 leucine-rich repeats leucine-rich repeats, and 2 C-terminal cysteines
- In contrast to decorin and biglycan , asporin is not a proteoglycan
- Instead, asporin contains a unique stretch of aspartic acid residues in its amino-terminal region
- A polymorphism was identified in that the number of consecutive aspartate residues varied from 11 to 15
- The 8 exons of the human asporin gene span 26 kilobases on chromosome 9q31.1-32, and the putative promoter region lacks TATA consensus sequences
- The asporin mRNA is expressed in a variety of human tissues with higher levels in osteoarthritic articular cartilage, aorta, uterus, heart, and liver
- The deduced amino acid sequence of asporin was confirmed by mass spectrometry of the isolated protein resulting in 84% sequence coverage
- The protein contains an N-glycosylation site at Asn(281) with a heterogeneous oligosaccharide structure and a potential O-glycosylation site at Ser(54)
- The name asporin reflects the aspartate-rich amino terminus and the overall similarity to decorin