Convergent evolution of sodium ion selectivity in metazoan neuronal signaling.

ABSTRACT: Ion selectivity of metazoan voltage-gated Na(+) channels is critical for neuronal signaling and has long been attributed to a ring of four conserved amino acids that constitute the ion selectivity filter (SF) at the channel pore. Yet, in addition to channels with a preference for Ca(2+) ions, the expression and characterization of Na(+) channel homologs from the sea anemone Nematostella vectensis, a member of the early-branching metazoan phylum Cnidaria, revealed a sodium-selective channel bearing a noncanonical SF. Mutagenesis and physiological assays suggest that pore elements additional to the SF determine the preference for Na(+) in this channel. Phylogenetic analysis assigns the Nematostella Na(+)-selective channel to a channel group unique to Cnidaria, which diverged >540 million yea

SUBMITTER: Gur Barzilai M 

PROVIDER: S-EPMC3809514 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature