A vast repertoire of Dscam binding specificities arises from modular interactions of variable Ig domains

TitleA vast repertoire of Dscam binding specificities arises from modular interactions of variable Ig domains
Publication TypeJournal Article
Year of Publication2007
AuthorsWojtowicz, W. M., Wu W., Andre I., Qian B., Baker D., & Zipursky L. S.
JournalCell
Volume130
Issue6
Pagination1134-45
Date Published2007 Sep 21
ISSN0092-8674
KeywordsAlternative Splicing, Animals, Binding Sites, Cell Adhesion Molecules, Cloning, Molecular, Collaborative Publication, Drosophila Proteins, Enzyme-Linked Immunosorbent Assay, Humans, Immunoglobulin Variable Region, Models, Molecular, Models, Neurological, Neurons, Protein Binding, Protein Conformation, Protein Isoforms, Protein Structure, Tertiary, Reproducibility of Results
Abstract

Dscam encodes a family of cell surface proteins required for establishing neural circuits in Drosophila. Alternative splicing of Drosophila Dscam can generate 19,008 distinct extracellular domains containing different combinations of three variable immunoglobulin domains. To test the binding properties of many Dscam isoforms, we developed a high-throughput ELISA-based binding assay. We provide evidence that 95% (>18,000) of Dscam isoforms exhibit striking isoform-specific homophilic binding. We demonstrate that each of the three variable domains binds to the same variable domain in an opposing isoform and identify the structural elements that mediate this self-binding of each domain. These studies demonstrate that self-binding domains can assemble in different combinations to generate an enormous family of homophilic binding proteins. We propose that this vast repertoire of Dscam recognition molecules is sufficient to provide each neuron with a unique identity and homotypic binding specificity, thereby allowing neuronal processes to distinguish between self and nonself.

Alternate JournalCell
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