title: Expression and structural studies of fasciclin I, an insect cell adhesion molecule.
abstract: Fasciclin I is a lipid-linked cell-surface glycoprotein that can act as a homophilic adhesion molecule in tissue culture cells. It is thought to be involved in growth cone guidance in the embryonic insect nervous system. To facilitate structure-function studies, we have generated Chinese hamster ovary (CHO) cell lines expressing high levels of cell surface grasshopper and Drosophila fasciclin I. Grasshopper fasciclin I released by phospholipase C cleavage was purified on an immunoaffinity column and single crystals were obtained that diffracted to approximately 5-A resolution. We also generated CHO and Drosophila S2 cell lines that produce a secreted form of fasciclin I. Fasciclin I expressed in S2 cells contains significantly less carbohydrate than the protein expressed in CHO cells, and may therefore be more suitable for crystallization. Biochemical characterization of purified fasciclin I indicates that the extracellular portion exists as a monomer in solution. Circular dichroism studies suggest that fasciclin I is primarily alpha-helical. Its structure is therefore different from other known cell adhesion molecules, which are predicted to be elongated beta-sheet structures. This suggests that fasciclin I may define a new structural motif used to mediate adhesive interactions between cell surfaces.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125.
authors.forename: W C
authors.initials: WC
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Zinn
authors.forename: P J
authors.initials: PJ
authors.lastname: Bjorkman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D015816:Cell Adhesion Molecules, Neuronal / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D002460:Cell Line; D002846:Chromatography, Affinity; D002942:Circular Dichroism; D006224:Cricetinae; D004330:Drosophila / Q000235:genetics* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004625:Embryo, Nonmammalian; D006110:Grasshoppers / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009424:Nervous System Physiological Phenomena; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D015183:Restriction Mapping; D013053:Spectrophotometry; D014162:Transfection
chemical_list: D015816:Cell Adhesion Molecules, Neuronal; D011994:Recombinant Proteins; C051641:fasciclin I