Drosophila Dscam Is an Axon Guidance Receptor Exhibiting Extraordinary Molecular Diversity

@article{Schmucker2000DrosophilaDI,
  title={Drosophila Dscam Is an Axon Guidance Receptor Exhibiting Extraordinary Molecular Diversity},
  author={Dietmar Schmucker and James C. Clemens and Huidy Shu and Carolyn A. Worby and Jian Xiao and Marco Muda and Jack E. Dixon and S. Lawrence Zipursky},
  journal={Cell},
  year={2000},
  volume={101},
  pages={671-684}
}
A Drosophila homolog of human Down syndrome cell adhesion molecule (DSCAM), an immunoglobulin superfamily member, was isolated by its affinity to Dock, an SH3/SH2 adaptor protein required for axon guidance. Dscam binds directly to both Dock's SH2 and SH3 domains. Genetic studies revealed that Dscam, Dock and Pak, a serine/threonine kinase, act together to direct pathfinding of Bolwig's nerve, containing a subclass of sensory axons, to an intermediate target in the embryo. Dscam also is required… 
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It is proposed that the ratio of matching to nonmatching isoforms within a cell influences the Dscam1-mediated signaling strength, which in turn controls axon growth and growth cone sprouting.
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TLDR
It is reported that cell-autonomous loss of the receptor tyrosine phosphatase 69D (RPTP69D) and loss of midline-localized Slit inhibit formation of specific axon collaterals through modulation of Dscam1 activity, enabling the spatial specificity of axon collateral formation.
Drosophila Vap-33 Is Required for Axonal Localization of Dscam Isoforms
TLDR
It is proposed that Vap function is required in neurons to selectively traffic proteins to axons, and disruption of this function may contribute to the pathology of ALS.
The Down Syndrome Cell Adhesion Molecule
The Down syndrome cell adhesion molecules (DSCAMs) are a structurally and functionally conserved family of cell surface receptors that play important roles in nervous system organization. These
Dscam and DSCAM: complex genes in simple animals, complex animals yet simple genes.
TLDR
How an unprecedented expansion of complex alternative splicing has been uniquely employed by arthropods to generate diverse surface receptors, important for cell-cell communication, molecular self-recognition in neurons, and innate immune defenses is discussed.
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