Genomic definition of RIM proteins: evolutionary amplification of a family of synaptic regulatory proteins.

摘要: RIMs are synaptic proteins that essential for normal neurotransmitter release. We now show while invertebrates contain only a single RIM gene, vertebrates four: two large genes encoding RIM1α (0.50 Mb) or RIM2α, 2β, and 2γ (0.50–0.75 smaller RIM3γ (14 kb) RIM4γ (55 kb). RIM2α consist of an N-terminal Zn2+-finger domain, central PDZ C2A domains, C-terminal C2B domain; RIM2β consists short β-specific sequence followed by domains RIM2γ, 3γ, 4γ domain. In the RIM2 transcribed from internal promoters. α- β-RIMs extensively alternatively spliced at three canonical positions, resulting in >200 variants differ up to 400 residues. Thus gene duplication, alternative splicing, multiple promoters diversify invertebrate into vertebrate protein family. The multiplicity may serve fine-tune release beyond fundamental, evolutionarily conserved, common function RIMs.