Cloning and characterization of AASPs: Novel axon-associated SH3 binding-like proteins

Two cDNAs encoding closely related proteins were isolated from a crayfish n ervous system lambda gt10 cDNA library with a rat synapsin Ia cDNA probe, T hese proteins were expressed exclusively in neurons, were highly enriched i n axons of the crayfish, and contained multiple, overlapping, putative Src homology 3 (SH3) binding sites, In concert with other proteins containing S rc homology domains, SH3 binding proteins are thought to mediate protein-pr otein interactions in receptor signaling processes and with the cytoskeleto n, We have named these proteins axon-associated SH3 binding-like proteins ( AASPs). Except for these SH3 binding regions, which are also found in synap sins, AASPs were unlike any proteins in the database. AASPs were differenti ally expressed among motoneuron populations in crayfish and were found in g rowing axons and growth cones in culture, Affinity purified polyclonal anti bodies to AASP-168 recognized immunoreactive proteins in rat and Xenopus, s uggesting that AASPs may be conserved across species. Although the cellular function of AASPs is unclear at this time, they appear to be novel members of a neuron-specific SH3 binding protein family, which includes the synaps ins, (C) 1999 John Wiley & Sons, Inc.