A novel N-terminal isoform of the neuron-specific K-Cl cotransporter KCC2

Pavel Uvarov, Anastasia Ludwig, Marika Markkanen, Priit Pruunsild, Kai Kaila, Eric Delpire, Tonis Timmusk, Claudio Rivera, Matti S. Airaksinen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The neuronal K-Cl cotransporter KCC2 maintains the low intracellular chloride concentration required for the hyperpolarizing actions of inhibitory neurotransmitters gamma-aminobutyric acid and glycine in the central nervous system. This study shows that the mammalian KCC2 gene ( alias Slc12a5) generates two neuron-specific isoforms by using alternative promoters and first exons. The novel KCC2a isoform differs from the only previously known KCC2 isoform (now termed KCC2b) by 40 unique N-terminal amino acid residues, including a putative Ste20-related proline alanine-rich kinase-binding site. Ribonuclease protection and quantitative PCR assays indicated that KCC2a contributes 20-50% of total KCC2 mRNA expression in the neonatal mouse brain stem and spinal cord. In contrast to the marked increase in KCC2b mRNA levels in the cortex during postnatal development, the overall expression of KCC2a remains relatively constant and makes up only 5-10% of total KCC2 mRNA in the mature cortex. A rubidium uptake assay in human embryonic kidney 293 cells showed that the KCC2a isoform mediates furosemide-sensitive ion transport activity comparable with that of KCC2b. Mice that lack both KCC2 isoforms die at birth due to severe motor defects, including disrupted respiratory rhythm, whereas mice with a targeted disruption of the first exon of KCC2b survive for up to 2 weeks but eventually die due to spontaneous seizures. We show that these mice lack KCC2b but retain KCC2a mRNA. Thus, distinct populations of neurons show a differential dependence on the expression of the two isoforms: KCC2a expression in the absence of KCC2b is presumably sufficient to support vital neuronal functions in the brain stem and spinal cord but not in the cortex.
Original languageEnglish
JournalJournal of Biological Chemistry
Volume282
Issue number42
Pages (from-to)30570-30576
Number of pages7
ISSN0021-9258
DOIs
Publication statusPublished - 2007
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 311 Basic medicine
  • 118 Biological sciences
  • 515 Psychology

Cite this

Uvarov, Pavel ; Ludwig, Anastasia ; Markkanen, Marika ; Pruunsild, Priit ; Kaila, Kai ; Delpire, Eric ; Timmusk, Tonis ; Rivera, Claudio ; Airaksinen, Matti S. / A novel N-terminal isoform of the neuron-specific K-Cl cotransporter KCC2. In: Journal of Biological Chemistry. 2007 ; Vol. 282, No. 42. pp. 30570-30576.
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title = "A novel N-terminal isoform of the neuron-specific K-Cl cotransporter KCC2",
abstract = "The neuronal K-Cl cotransporter KCC2 maintains the low intracellular chloride concentration required for the hyperpolarizing actions of inhibitory neurotransmitters gamma-aminobutyric acid and glycine in the central nervous system. This study shows that the mammalian KCC2 gene ( alias Slc12a5) generates two neuron-specific isoforms by using alternative promoters and first exons. The novel KCC2a isoform differs from the only previously known KCC2 isoform (now termed KCC2b) by 40 unique N-terminal amino acid residues, including a putative Ste20-related proline alanine-rich kinase-binding site. Ribonuclease protection and quantitative PCR assays indicated that KCC2a contributes 20-50{\%} of total KCC2 mRNA expression in the neonatal mouse brain stem and spinal cord. In contrast to the marked increase in KCC2b mRNA levels in the cortex during postnatal development, the overall expression of KCC2a remains relatively constant and makes up only 5-10{\%} of total KCC2 mRNA in the mature cortex. A rubidium uptake assay in human embryonic kidney 293 cells showed that the KCC2a isoform mediates furosemide-sensitive ion transport activity comparable with that of KCC2b. Mice that lack both KCC2 isoforms die at birth due to severe motor defects, including disrupted respiratory rhythm, whereas mice with a targeted disruption of the first exon of KCC2b survive for up to 2 weeks but eventually die due to spontaneous seizures. We show that these mice lack KCC2b but retain KCC2a mRNA. Thus, distinct populations of neurons show a differential dependence on the expression of the two isoforms: KCC2a expression in the absence of KCC2b is presumably sufficient to support vital neuronal functions in the brain stem and spinal cord but not in the cortex.",
keywords = "311 Basic medicine, 118 Biological sciences, 515 Psychology",
author = "Pavel Uvarov and Anastasia Ludwig and Marika Markkanen and Priit Pruunsild and Kai Kaila and Eric Delpire and Tonis Timmusk and Claudio Rivera and Airaksinen, {Matti S.}",
year = "2007",
doi = "10.1074/jbc.M705095200",
language = "English",
volume = "282",
pages = "30570--30576",
journal = "Journal of Biological Chemistry",
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A novel N-terminal isoform of the neuron-specific K-Cl cotransporter KCC2. / Uvarov, Pavel; Ludwig, Anastasia; Markkanen, Marika; Pruunsild, Priit; Kaila, Kai; Delpire, Eric; Timmusk, Tonis; Rivera, Claudio; Airaksinen, Matti S.

In: Journal of Biological Chemistry, Vol. 282, No. 42, 2007, p. 30570-30576.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - A novel N-terminal isoform of the neuron-specific K-Cl cotransporter KCC2

AU - Uvarov, Pavel

AU - Ludwig, Anastasia

AU - Markkanen, Marika

AU - Pruunsild, Priit

AU - Kaila, Kai

AU - Delpire, Eric

AU - Timmusk, Tonis

AU - Rivera, Claudio

AU - Airaksinen, Matti S.

PY - 2007

Y1 - 2007

N2 - The neuronal K-Cl cotransporter KCC2 maintains the low intracellular chloride concentration required for the hyperpolarizing actions of inhibitory neurotransmitters gamma-aminobutyric acid and glycine in the central nervous system. This study shows that the mammalian KCC2 gene ( alias Slc12a5) generates two neuron-specific isoforms by using alternative promoters and first exons. The novel KCC2a isoform differs from the only previously known KCC2 isoform (now termed KCC2b) by 40 unique N-terminal amino acid residues, including a putative Ste20-related proline alanine-rich kinase-binding site. Ribonuclease protection and quantitative PCR assays indicated that KCC2a contributes 20-50% of total KCC2 mRNA expression in the neonatal mouse brain stem and spinal cord. In contrast to the marked increase in KCC2b mRNA levels in the cortex during postnatal development, the overall expression of KCC2a remains relatively constant and makes up only 5-10% of total KCC2 mRNA in the mature cortex. A rubidium uptake assay in human embryonic kidney 293 cells showed that the KCC2a isoform mediates furosemide-sensitive ion transport activity comparable with that of KCC2b. Mice that lack both KCC2 isoforms die at birth due to severe motor defects, including disrupted respiratory rhythm, whereas mice with a targeted disruption of the first exon of KCC2b survive for up to 2 weeks but eventually die due to spontaneous seizures. We show that these mice lack KCC2b but retain KCC2a mRNA. Thus, distinct populations of neurons show a differential dependence on the expression of the two isoforms: KCC2a expression in the absence of KCC2b is presumably sufficient to support vital neuronal functions in the brain stem and spinal cord but not in the cortex.

AB - The neuronal K-Cl cotransporter KCC2 maintains the low intracellular chloride concentration required for the hyperpolarizing actions of inhibitory neurotransmitters gamma-aminobutyric acid and glycine in the central nervous system. This study shows that the mammalian KCC2 gene ( alias Slc12a5) generates two neuron-specific isoforms by using alternative promoters and first exons. The novel KCC2a isoform differs from the only previously known KCC2 isoform (now termed KCC2b) by 40 unique N-terminal amino acid residues, including a putative Ste20-related proline alanine-rich kinase-binding site. Ribonuclease protection and quantitative PCR assays indicated that KCC2a contributes 20-50% of total KCC2 mRNA expression in the neonatal mouse brain stem and spinal cord. In contrast to the marked increase in KCC2b mRNA levels in the cortex during postnatal development, the overall expression of KCC2a remains relatively constant and makes up only 5-10% of total KCC2 mRNA in the mature cortex. A rubidium uptake assay in human embryonic kidney 293 cells showed that the KCC2a isoform mediates furosemide-sensitive ion transport activity comparable with that of KCC2b. Mice that lack both KCC2 isoforms die at birth due to severe motor defects, including disrupted respiratory rhythm, whereas mice with a targeted disruption of the first exon of KCC2b survive for up to 2 weeks but eventually die due to spontaneous seizures. We show that these mice lack KCC2b but retain KCC2a mRNA. Thus, distinct populations of neurons show a differential dependence on the expression of the two isoforms: KCC2a expression in the absence of KCC2b is presumably sufficient to support vital neuronal functions in the brain stem and spinal cord but not in the cortex.

KW - 311 Basic medicine

KW - 118 Biological sciences

KW - 515 Psychology

U2 - 10.1074/jbc.M705095200

DO - 10.1074/jbc.M705095200

M3 - Article

VL - 282

SP - 30570

EP - 30576

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 42

ER -