Ca2+ channel modulation by recombinant auxiliary β subunits expressed in young adult heart cells

Shao Kui Wei, Henry M. Colecraft, Carla D. DeMaria, Blaise Z. Peterson, Rui Zhang, Trudy A. Kohout, Terry B. Rogers, David T. Yue

Research output: Contribution to journalArticle

Abstract

L-type Ca2+ channels contribute importantly to the normal excitation- contraction coupling of physiological hearts, and to the functional derangement seen in heart failure. Although Ca2+ channel auxiliary β1-4 subunits are among the strongest modulators of channel properties, little is known about their role in regulating channel behavior in actual heart cells. Current understanding draws almost exclusively from heterologous expression of recombinant subunits in model systems, which may differ from cardiocytes. To study β-subunit effects in the cardiac setting, we here used an adenoviral-component gene-delivery strategy to express recombinant β subunits in young adult ventricular myocytes cultured from 4- to 6-week-old rats. The main results were the following. (1) A component system of replication-deficient adenovirus, poly-L-lysine, and expression plasmids encoding β subunits could be optimized to transfect young adult myocytes with 1% to 10% efficiency. (2) A reporter gene strategy based on green fluorescent protein (GFP) could be used to identify successfully transfected cells. Because fusion of GFP to β subunits altered intrinsic β-subunit properties, we favored the use of a bicistronic expression plasmid encoding both GFP and a β subunit. (3) Despite the heteromultimeric composition of L- type channels (composed of α(1C), β, and α2δ), expression of recombinant β subunits alone enhanced Ca2+ channel current density up to 3- to 4-fold, which argues that β subunits are 'ate limiting' for expression of current in heart. (4) Overexpression of the putative 'cardiac' β(2a) subunit more than halved the rate of voltage-dependent inactivation at + 10 mV. This result demonstrates that β subunits can tune inactivation in the myocardium and suggests that other β subunits may be functionally dominant in the heart. Overall, this study points to the possible therapeutic potential of β subunits to ameliorate contractile dysfunction and excitability in heart failure.

Original languageEnglish (US)
Pages (from-to)175-184
Number of pages10
JournalCirculation Research
Volume86
Issue number2
StatePublished - 2000

Fingerprint

Young Adult
Green Fluorescent Proteins
Protein Subunits
Muscle Cells
Plasmids
Heart Failure
Gene Components
Excitation Contraction Coupling
Reporter Genes
Adenoviridae
Lysine
Myocardium
Therapeutics

Keywords

  • β subunit
  • Adenovirus
  • Ca channel
  • Gene delivery

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Wei, S. K., Colecraft, H. M., DeMaria, C. D., Peterson, B. Z., Zhang, R., Kohout, T. A., ... Yue, D. T. (2000). Ca2+ channel modulation by recombinant auxiliary β subunits expressed in young adult heart cells. Circulation Research, 86(2), 175-184.

Ca2+ channel modulation by recombinant auxiliary β subunits expressed in young adult heart cells. / Wei, Shao Kui; Colecraft, Henry M.; DeMaria, Carla D.; Peterson, Blaise Z.; Zhang, Rui; Kohout, Trudy A.; Rogers, Terry B.; Yue, David T.

In: Circulation Research, Vol. 86, No. 2, 2000, p. 175-184.

Research output: Contribution to journalArticle

Wei, SK, Colecraft, HM, DeMaria, CD, Peterson, BZ, Zhang, R, Kohout, TA, Rogers, TB & Yue, DT 2000, 'Ca2+ channel modulation by recombinant auxiliary β subunits expressed in young adult heart cells', Circulation Research, vol. 86, no. 2, pp. 175-184.
Wei SK, Colecraft HM, DeMaria CD, Peterson BZ, Zhang R, Kohout TA et al. Ca2+ channel modulation by recombinant auxiliary β subunits expressed in young adult heart cells. Circulation Research. 2000;86(2):175-184.
Wei, Shao Kui ; Colecraft, Henry M. ; DeMaria, Carla D. ; Peterson, Blaise Z. ; Zhang, Rui ; Kohout, Trudy A. ; Rogers, Terry B. ; Yue, David T. / Ca2+ channel modulation by recombinant auxiliary β subunits expressed in young adult heart cells. In: Circulation Research. 2000 ; Vol. 86, No. 2. pp. 175-184.
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