Abstract
Rationale: Ca2+-activated K+ channels are present in a wide variety of cells. We have previously reported the presence of small conductance Ca2+-activated K+ (SK or KCa) channels in human and mouse cardiac myocytes that contribute functionally toward the shape and duration of cardiac action potentials. Three isoforms of SK channel subunits (SK1, SK2, and SK3) are found to be expressed. Moreover, there is differential expression with more abundant SK channels in the atria and pacemaking tissues compared with the ventricles. SK channels are proposed to be assembled as tetramers similar to other K+ channels, but the molecular determinants driving their subunit interaction and assembly are not defined in cardiac tissues. Objective: To investigate the heteromultimeric formation and the domain necessary for the assembly of 3 SK channel subunits (SK1, SK2, and SK3) into complexes in human and mouse hearts. Methods and Results: Here, we provide evidence to support the formation of heteromultimeric complexes among different SK channel subunits in native cardiac tissues. SK1, SK2, and SK3 subunits contain coiled-coil domains (CCDs) in the C termini. In vitro interaction assay supports the direct interaction between CCDs of the channel subunits. Moreover, specific inhibitory peptides derived from CCDs block the Ca2+-activated K+ current in atrial myocytes, which is important for cardiac repolarization. Conclusions: The data provide evidence for the formation of heteromultimeric complexes among different SK channel subunits in atrial myocytes. Because SK channels are predominantly expressed in atrial myocytes, specific ligands of the different isoforms of SK channel subunits may offer a unique therapeutic opportunity to directly modify atrial cells without interfering with ventricular myocytes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 851-859 |
| Number of pages | 9 |
| Journal | Circulation Research |
| Volume | 107 |
| Issue number | 7 |
| DOIs | |
| State | Published - Oct 1 2010 |
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Keywords
- Ca-activated K channels
- cardiac myocytes
- coiled-coil domains
- heteromultimerization
ASJC Scopus subject areas
- Physiology
- Cardiology and Cardiovascular Medicine
- Medicine(all)
Cite this
Cardiac small conductance Ca2+-activated K+ channel subunits form heteromultimers via the coiled-coil domains in the C termini of the channels. / Tuteja, Dipika; Rafizadeh, Sassan; Timofeyev, Valeriy; Wang, Shuyun; Zhang, Zheng; Li, Ning; Mateo, Robertino K.; Singapuri, Anil; Young, J Nilas; Knowlton, Anne A; Chiamvimonvat, Nipavan.
In: Circulation Research, Vol. 107, No. 7, 01.10.2010, p. 851-859.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cardiac small conductance Ca2+-activated K+ channel subunits form heteromultimers via the coiled-coil domains in the C termini of the channels
AU - Tuteja, Dipika
AU - Rafizadeh, Sassan
AU - Timofeyev, Valeriy
AU - Wang, Shuyun
AU - Zhang, Zheng
AU - Li, Ning
AU - Mateo, Robertino K.
AU - Singapuri, Anil
AU - Young, J Nilas
AU - Knowlton, Anne A
AU - Chiamvimonvat, Nipavan
PY - 2010/10/1
Y1 - 2010/10/1
N2 - Rationale: Ca2+-activated K+ channels are present in a wide variety of cells. We have previously reported the presence of small conductance Ca2+-activated K+ (SK or KCa) channels in human and mouse cardiac myocytes that contribute functionally toward the shape and duration of cardiac action potentials. Three isoforms of SK channel subunits (SK1, SK2, and SK3) are found to be expressed. Moreover, there is differential expression with more abundant SK channels in the atria and pacemaking tissues compared with the ventricles. SK channels are proposed to be assembled as tetramers similar to other K+ channels, but the molecular determinants driving their subunit interaction and assembly are not defined in cardiac tissues. Objective: To investigate the heteromultimeric formation and the domain necessary for the assembly of 3 SK channel subunits (SK1, SK2, and SK3) into complexes in human and mouse hearts. Methods and Results: Here, we provide evidence to support the formation of heteromultimeric complexes among different SK channel subunits in native cardiac tissues. SK1, SK2, and SK3 subunits contain coiled-coil domains (CCDs) in the C termini. In vitro interaction assay supports the direct interaction between CCDs of the channel subunits. Moreover, specific inhibitory peptides derived from CCDs block the Ca2+-activated K+ current in atrial myocytes, which is important for cardiac repolarization. Conclusions: The data provide evidence for the formation of heteromultimeric complexes among different SK channel subunits in atrial myocytes. Because SK channels are predominantly expressed in atrial myocytes, specific ligands of the different isoforms of SK channel subunits may offer a unique therapeutic opportunity to directly modify atrial cells without interfering with ventricular myocytes.
AB - Rationale: Ca2+-activated K+ channels are present in a wide variety of cells. We have previously reported the presence of small conductance Ca2+-activated K+ (SK or KCa) channels in human and mouse cardiac myocytes that contribute functionally toward the shape and duration of cardiac action potentials. Three isoforms of SK channel subunits (SK1, SK2, and SK3) are found to be expressed. Moreover, there is differential expression with more abundant SK channels in the atria and pacemaking tissues compared with the ventricles. SK channels are proposed to be assembled as tetramers similar to other K+ channels, but the molecular determinants driving their subunit interaction and assembly are not defined in cardiac tissues. Objective: To investigate the heteromultimeric formation and the domain necessary for the assembly of 3 SK channel subunits (SK1, SK2, and SK3) into complexes in human and mouse hearts. Methods and Results: Here, we provide evidence to support the formation of heteromultimeric complexes among different SK channel subunits in native cardiac tissues. SK1, SK2, and SK3 subunits contain coiled-coil domains (CCDs) in the C termini. In vitro interaction assay supports the direct interaction between CCDs of the channel subunits. Moreover, specific inhibitory peptides derived from CCDs block the Ca2+-activated K+ current in atrial myocytes, which is important for cardiac repolarization. Conclusions: The data provide evidence for the formation of heteromultimeric complexes among different SK channel subunits in atrial myocytes. Because SK channels are predominantly expressed in atrial myocytes, specific ligands of the different isoforms of SK channel subunits may offer a unique therapeutic opportunity to directly modify atrial cells without interfering with ventricular myocytes.
KW - Ca-activated K channels
KW - cardiac myocytes
KW - coiled-coil domains
KW - heteromultimerization
UR - http://www.scopus.com/inward/record.url?scp=77957999471&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77957999471&partnerID=8YFLogxK
U2 - 10.1161/CIRCRESAHA.109.215269
DO - 10.1161/CIRCRESAHA.109.215269
M3 - Article
C2 - 20689065
AN - SCOPUS:77957999471
VL - 107
SP - 851
EP - 859
JO - Circulation Research
JF - Circulation Research
SN - 0009-7330
IS - 7
ER -