Identification and characterization of a novel interaction between pulmonary surfactant protein D and decorin.

Nadesalingam, J; Bernal, A; Dodds, A; Willis, A; Mahoney, D; Day, A; Reid, K; Palaniyar, N

Journal article

Identification and characterization of a novel interaction between pulmonary surfactant protein D and decorin.

Abstract:: Surfactant-associated protein D (SP-D) is a collectin that is present in lung surfactant and mucosal surfaces. Although SP-D regulates diverse functions, only a few proteins are known to bind to this collectin. Here we describe the co-purification of decorin, a novel SP-D-binding protein, from amniotic fluid. The human decorin that co-purified with SP-D is a 130-150-kDa proteoglycan, which has a 46-kDa protein core and approximately 90-kDa dermatan sulfate chain. Both native and recombinant decorin can bind to SP-D that is already bound to maltose-agarose matrix, and these SP-D-decorin complexes are dissociated at high salt (0.5-1.0 m NaCl) conditions, releasing the decorin. We further show that SP-D and decorin interact with each other (kd = 4 nm) by two mechanisms. First, the direct binding and competition experiments show that the carbohydrate recognition domain (CRD) of SP-D binds in a calcium dependent-manner to the sulfated N-acetyl galactosamine moiety of the glycosaminoglycan chain. Second, complement component C1q, a complement protein that is known to interact with decorin core protein via its collagen-like region, partially blocks the interaction between decorin and native SP-D. This protein, however, does not block the interaction between decorin and SP-D(n/CRD), a recombinant fragment that lacks the N-terminal and collagen-like regions. Furthermore, the core protein, obtained by chondroitin ABC lyase treatment of decorin, binds SP-D, but not SP-D(n/CRD). These findings suggest that decorin core protein binds the collagen-like region of the SP-D. Concentrations of decorin and SP-D are negatively correlated to each other, in amniotic fluid, implying a functional relevance for SP-D-decorin interaction, in vivo. Collectively, our results show that carbohydrate recognition domains of SP-D interact with the dermatan sulfate moiety of decorin via lectin activity and that the core protein of decorin binds the collagen-like region of SP-D in vitro, and these interactions may be operative in vivo.

Publication status:: Published

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APA Style

Nadesalingam, J., Bernal, A., Dodds, A., Willis, A., Mahoney, D., Day, A., Reid, K., & Palaniyar, N. (2003). Identification and characterization of a novel interaction between pulmonary surfactant protein D and decorin. Journal of Biological Chemistry, 278(28), 25678–25687.

MLA Style

Nadesalingam, J, et al. “Identification and Characterization of a Novel Interaction between Pulmonary Surfactant Protein D and Decorin.” Journal of Biological Chemistry, vol. 278, no. 28, 2003, pp. 25678–87.

Chicago Style

Nadesalingam, J, A Bernal, A Dodds, et al. 2003. “Identification and Characterization of a Novel Interaction between Pulmonary Surfactant Protein D and Decorin.” Journal of Biological Chemistry 278 (28): 25678–87.
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