Regular article
Kv3.3 Potassium Channels in Lens Epithelium and Corneal Endothelium

https://doi.org/10.1006/exer.1999.0796Get rights and content

Abstract

Human Kv3.3/KCNC3 is a Shaw-type potassium channel that has been mapped to chromosome 19q13.3–13.4. Complete mouse and rat Kv3.3 cDNA coding sequences have been published, yet the human Kv3.3 cDNA has remained incomplete for years. We report here for the first time the amino acid sequence for hKv3.3 and the electrophysiological behavior of the encoded channel in transiently transfected mammalian cells. In addition, we report the occurrence of Kv3.3 message in rabbit corneal endothelial cells and the properties of the currents when the corneal channel is expressed. The hKv3.3 gene is highly GC-rich (69%) and contains numerous GC runs which made DNA sequencing and PCR amplification especially problematic. The full-length sequence contains two possible start codons. The encoded 757 amino acid hKv3.3 protein is about 93% identical to mouse and rat Kv3.3 in the first 659 amino acids before the C-terminal domains diverge greatly as a result of alternative splicing. The rabbit cornea Kv3.3 is a close sequence match for hKv3.3 even in the C-terminal domain. However, we have not yet found a cornea sequence which contains the first potential start codon from hKv3.3. Electrophysiologically, the hKv3.3 channel produces an A-current although expression of constructs which lack the 5′ region of the first start codon inactivate much more slowly than full-length constructs. This short hKv3.3 construct also shows changes in activation.

References (23)

  • J.L. Rae

    Outwardly rectifying potassium currents in lens epithelial cell membranes

    Curr. Eye Res.

    (1994)
  • Cited by (32)

    • Pharmacological inhibition of Kv3 on oxidative stress-induced cataract progression

      2020, Biochemical and Biophysical Research Communications
      Citation Excerpt :

      Accordingly, oxidation of sulfur-containing amino acids is important in both the cataractogenesis and function of Kv3.4, and Kv3.4 may therefore play pivotal roles in oxidative stress-induced cataractogenesis. In addition, Kv3.3 and Kv3.4 are already known to be localized in several different parts of eyes such as lens epithelium, corneal epithelium and corneal endothelium [39,40]. Indeed, our data showed that blocking the oxidation-sensitive Kv channel by BDS-II efficiently inhibited cataract progression.

    • Effects of amantadine on corneal endothelium

      2019, Experimental Eye Research
    • Protein kinase C modulates inactivation of Kv3.3 channels

      2008, Journal of Biological Chemistry
      Citation Excerpt :

      Like other members of the Kv3 family, murine Kv3.3 channels display rapid activation and deactivation kinetics and a high threshold of voltage activation. Rates of activation and inactivation of mouse Kv3.3 channels are quantitatively similar to those of the full-length human Kv3.3 channel, although their rate of deactivation is approximately twice as fast as that reported for the human channels (32). Somewhat greater differences are seen when comparing the properties of murine Kv3.3 channels with those of previously described Apteronotus Kv3.3 channels quantified in CHO cells (33).

    View all citing articles on Scopus
    f1

    Address correspondence to: James L. Rae, Departments of Physiology and Biophysics and Ophthalmology, Room 934 Guggenheim Bldg., Mayo Foundation, 200 First Street SW, Rochester, MN 55905, U.S.A.

    View full text