Voltage-gated Na+ channel β1 subunit mRNA expressed in adult human skeletal muscle, heart, and brain is encoded by a single gene

Naomasa Makita, Paul B. Bennett, Alfred L. George*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

136 Scopus citations


Voltage-gated Na+ channels are heteromeric proteins consisting of α and β subunits. Although α subunits alone are sufficient to encode functional channels, β1 subunits appear to modulate the kinetics of inactivation. We have used a cross-species reverse transcriptase polymerase chain reaction approach to isolate cDNAs encoding a Na+ channel β1 subunit from human heart and skeletal muscle. The deduced amino acid sequence of the human β1 subunit exhibits 96% identity with the rat brain β1 subunit. Human β1 mRNA transcripts are abundantly expressed in skeletal muscle, heart, and brain. Genomic Southern blot hybridization experiments suggest that a single gene located on chromosome 19 encodes the human β1 subunit that is expressed in all three of these tissues. Co-expression of the human β1 subunit with the recombinant human skeletal muscle α subunit (hSkM1) in Xenopus oocytes results in Na+ currents that inactivate rapidly. In contrast, the human β1 subunit has no effect on the function of the tetrodotoxin-insensitive human heart Na+ channel (hH1). These findings indicate that the human β1 subunit is widely expressed but does not functionally modify all Na+ channel isoforms.

Original languageEnglish (US)
Pages (from-to)7571-7578
Number of pages8
JournalJournal of Biological Chemistry
Issue number10
StatePublished - Mar 11 1994

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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