Abstract
The voltage-gated potassium (Kv) channel Kv1.5 mediates the IKur repolarizing current in human atrial myocytes and regulates vascular tone in multiple peripheral vascular beds. Understanding the complex regulation of Kv1.5 function is of substantial interest because it represents a promising pharmacological target for the treatment of atrial fibrillation and hypoxic pulmonary hypertension. Herein we demonstrate that posttranslational modification of Kv1.5 by small ubiquitin-like modifier (SUMO) proteins modulates Kv1.5 function. We have identified two membrane-proximal and highly conserved cytoplasmic sequences in Kv1.5 that conform to established SUMO modification sites in transcription factors. We find that Kv1.5 interacts specifically with the SUMO-conjugating enzyme Ubc9 and is a target for modification by SUMO-1, -2, and -3 in vivo. In addition, purified recombinant Kv1.5 serves as a substrate in a minimal in vitro reconstituted SUMOylation reaction. The SUMO-specific proteases SENP2 and Ulp1 efficiently deconjugate SUMO from Kv1.5 in vivo and in vitro, and disruption of the two identified target motifs results in a loss of the major SUMO-conjugated forms of Kv1.5. In whole-cell patch-clamp electrophysiological studies, loss of Kv1.5 SUMOylation, by either disruption of the conjugation sites or expression of the SUMO protease SENP2, leads to a selective ≈15-mV hyperpolarizing shift in the voltage dependence of steady-state inactivation. Reversible control of voltage-sensitive channels through SUMOylation constitutes a unique and likely widespread mechanism for adaptive tuning of the electrical excitability of cells.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1805-1810 |
| Number of pages | 6 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 104 |
| Issue number | 6 |
| DOIs | |
| State | Published - Feb 6 2007 |
| Externally published | Yes |
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Keywords
- Electrical excitability
- Posttranslational modification
- Transmembrane protein
- Ubiquitin-like modifier
ASJC Scopus subject areas
- Genetics
- General
Cite this
SUMO modification regulates inactivation of the voltage-gated potassium channel Kv1.5. / Benson, Mark D.; Li, Qiu Ju; Kieckhafer, Katherine; Dudek, David; Whorton, Matthew; Sunahara, Roger K.; Iñiguez-Lluhí, Jorge A.; Martens, Jeffrey R.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 104, No. 6, 06.02.2007, p. 1805-1810.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - SUMO modification regulates inactivation of the voltage-gated potassium channel Kv1.5
AU - Benson, Mark D.
AU - Li, Qiu Ju
AU - Kieckhafer, Katherine
AU - Dudek, David
AU - Whorton, Matthew
AU - Sunahara, Roger K.
AU - Iñiguez-Lluhí, Jorge A.
AU - Martens, Jeffrey R.
PY - 2007/2/6
Y1 - 2007/2/6
N2 - The voltage-gated potassium (Kv) channel Kv1.5 mediates the IKur repolarizing current in human atrial myocytes and regulates vascular tone in multiple peripheral vascular beds. Understanding the complex regulation of Kv1.5 function is of substantial interest because it represents a promising pharmacological target for the treatment of atrial fibrillation and hypoxic pulmonary hypertension. Herein we demonstrate that posttranslational modification of Kv1.5 by small ubiquitin-like modifier (SUMO) proteins modulates Kv1.5 function. We have identified two membrane-proximal and highly conserved cytoplasmic sequences in Kv1.5 that conform to established SUMO modification sites in transcription factors. We find that Kv1.5 interacts specifically with the SUMO-conjugating enzyme Ubc9 and is a target for modification by SUMO-1, -2, and -3 in vivo. In addition, purified recombinant Kv1.5 serves as a substrate in a minimal in vitro reconstituted SUMOylation reaction. The SUMO-specific proteases SENP2 and Ulp1 efficiently deconjugate SUMO from Kv1.5 in vivo and in vitro, and disruption of the two identified target motifs results in a loss of the major SUMO-conjugated forms of Kv1.5. In whole-cell patch-clamp electrophysiological studies, loss of Kv1.5 SUMOylation, by either disruption of the conjugation sites or expression of the SUMO protease SENP2, leads to a selective ≈15-mV hyperpolarizing shift in the voltage dependence of steady-state inactivation. Reversible control of voltage-sensitive channels through SUMOylation constitutes a unique and likely widespread mechanism for adaptive tuning of the electrical excitability of cells.
AB - The voltage-gated potassium (Kv) channel Kv1.5 mediates the IKur repolarizing current in human atrial myocytes and regulates vascular tone in multiple peripheral vascular beds. Understanding the complex regulation of Kv1.5 function is of substantial interest because it represents a promising pharmacological target for the treatment of atrial fibrillation and hypoxic pulmonary hypertension. Herein we demonstrate that posttranslational modification of Kv1.5 by small ubiquitin-like modifier (SUMO) proteins modulates Kv1.5 function. We have identified two membrane-proximal and highly conserved cytoplasmic sequences in Kv1.5 that conform to established SUMO modification sites in transcription factors. We find that Kv1.5 interacts specifically with the SUMO-conjugating enzyme Ubc9 and is a target for modification by SUMO-1, -2, and -3 in vivo. In addition, purified recombinant Kv1.5 serves as a substrate in a minimal in vitro reconstituted SUMOylation reaction. The SUMO-specific proteases SENP2 and Ulp1 efficiently deconjugate SUMO from Kv1.5 in vivo and in vitro, and disruption of the two identified target motifs results in a loss of the major SUMO-conjugated forms of Kv1.5. In whole-cell patch-clamp electrophysiological studies, loss of Kv1.5 SUMOylation, by either disruption of the conjugation sites or expression of the SUMO protease SENP2, leads to a selective ≈15-mV hyperpolarizing shift in the voltage dependence of steady-state inactivation. Reversible control of voltage-sensitive channels through SUMOylation constitutes a unique and likely widespread mechanism for adaptive tuning of the electrical excitability of cells.
KW - Electrical excitability
KW - Posttranslational modification
KW - Transmembrane protein
KW - Ubiquitin-like modifier
UR - http://www.scopus.com/inward/record.url?scp=33846914818&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846914818&partnerID=8YFLogxK
U2 - 10.1073/pnas.0606702104
DO - 10.1073/pnas.0606702104
M3 - Article
VL - 104
SP - 1805
EP - 1810
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 6
ER -