Interaction between the transcriptional corepressor Sin3B and voltage-gated sodium channels modulates functional channel expression.
Proteins that interact with voltage-gated sodium (Na(v)) channels are important in channel sorting and modulation. In this study, we identified the transcriptional regulator, Sin3B, as a novel binding partner of Na(v) channels in a yeast two-hybrid screen and confirmed the interaction using pull-down assays, co-immunoprecipitation, and immunofluorescence-colocalization. Because both long (~1100-residue) and short (N-terminal 293 residues) Sin3B variants interacted with Na(v) channels, binding occurred within the N-terminal region containing two paired-amphipathic helix domains. In Na(v) channels, Sin3B bound to a 132-residue portion of the cytoplasmic C-terminus. Expression of the short Sin3B variant strongly reduced native sodium current and Na(v)-channel gating charge in the neuronal cell line N1E-115, without affecting the voltage-dependence of activation. Because the total amount of channel protein was unchanged by Sin3B, binding of Sin3B likely decreases the number of channels in the plasma membrane, suggesting that interaction with Sin3B influences Na(v)-channel trafficking or stability in the membrane.
Carrera de Médico Cirujano. UBIMED. FES Iztacala, UNAM. Los Reyes Iztacala. Edo, Mex. 54090 México.
Ana V
AV
Vega
Guillermo
G
Avila
Gary
G
Matthews
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D056970:Co-Repressor Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D051379:Mice; D008969:Molecular Sequence Data; D062551:NAV1.2 Voltage-Gated Sodium Channel / Q000737:chemistry / Q000378:metabolism*; D062557:NAV1.6 Voltage-Gated Sodium Channel / Q000737:chemistry / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D056970:Co-Repressor Proteins; D062551:NAV1.2 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D012097:Repressor Proteins; C115812:Sin3b protein, mouse