The lung lectin surfactant protein A aggregates phospholipid vesicles via a novel mechanism.
Surfactant protein A (SP-A), a lung-specific glycoprotein, consists of an N-terminal collagen-like domain and a C-terminal domain with a sequence similar to that of several Ca2(+)-dependent lectins. SP-A induces a rapid Ca2(+)-dependent aggregation of phospholipid vesicles. We report here that vesicle aggregation is mediated by Ca2(+)-induced interactions between carbohydrate-binding domains and oligosaccharide moieties of SP-A. This novel mechanism of membrane interactions may be relevant to the formation of the membrane lattice of tubular myelin, an extracellular form of surfactant.
Haagsman
H P
HP
Laboratory of Veterinary Biochemistry, Medical Faculty, University of Utrecht, The Netherlands.
Elfring
R H
RH
van Buel
B L
BL
Voorhout
W F
WF
D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D005614:Freeze Fracturing; D006031:Glycosylation; D006801:Humans; D008081:Liposomes / Q000378:metabolism*; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D009844:Oligosaccharides / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism / Q000494:pharmacology*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism / Q000494:pharmacology*
D008081:Liposomes; D046911:Macromolecular Substances; D009844:Oligosaccharides; D010743:Phospholipids; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D002118:Calcium