ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
We have identified an alternatively spliced form of synaptotagmin I in Aplysia neurons. This isoform, synaptotagmin I C2B-β, is generated by alternative exon usage in the C2B domain leading to nine amino acid changes in the C2B sequence from the previously characterized synaptotagmin I, now designated as synaptotagmin I C2B-α. Quantitative reverse transcriptase-polymerase chain reaction demonstrated that approximately 25% of mRNA encoding synaptotagmin I contained the C2B-β exon in the nervous system. Synaptotagmin I C2B-β showed greater resistance to digestion by chymotrypsin in the absence of calcium than did synaptotagmin I C2B-α, although both isoforms required the same amount of calcium to resist chymotrypsin digestion. The source of these changes in C2B properties was mapped to a single amino acid (threonine 358). We have also cloned SNAP 25 in Aplysia and show that it binds synaptotagmin I C2B-β with a higher affinity than synaptotagmin I C2B-α. These results suggest that this splicing alters biochemical properties of the C2B domain, affecting a number of its important known interactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.2004.02325.x
