α-Actinin Promotes Surface Localization and Current Density of the Ca2+ Channel CaV1.2 by Binding to the IQ Region of the α1 Subunit

Pang Yen Tseng, Peter B. Henderson, Anne C. Hergarden, Tommaso Patriarchi, Andrea M. Coleman, Mark W. Lillya, Carlota Montagut-Bordas, Boram Lee, Johannes W Hell, Mary C Horne

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The voltage-gated L-type Ca2+ channel CaV1.2 is crucial for initiating heartbeat and control of a number of neuronal functions such as neuronal excitability and long-term potentiation. Mutations of CaV1.2 subunits result in serious health problems, including arrhythmia, autism spectrum disorders, immunodeficiency, and hypoglycemia. Thus, precise control of CaV1.2 surface expression and localization is essential. We previously reported that α-actinin associates and colocalizes with neuronal CaV1.2 channels and that shRNA-mediated depletion of α-actinin significantly reduces localization of endogenous CaV1.2 in dendritic spines in hippocampal neurons. Here we investigated the hypothesis that direct binding of α-actinin to CaV1.2 supports its surface expression. Using two-hybrid screens and pull-down assays, we identified three point mutations (K1647A, Y1649A, and I1654A) in the central, pore-forming α11.2 subunit of CaV1.2 that individually impaired α-actinin binding. Surface biotinylation and flow cytometry assays revealed that CaV1.2 channels composed of the corresponding α-actinin-binding-deficient mutants result in a 35-40% reduction in surface expression compared to that of wild-type channels. Moreover, the mutant CaV1.2 channels expressed in HEK293 cells exhibit a 60-75% decrease in current density. The larger decrease in current density as compared to surface expression imparted by these α11.2 subunit mutations hints at the possibility that α-actinin not only stabilizes surface localization of CaV1.2 but also augments its ion conducting activity.

Original languageEnglish (US)
Pages (from-to)3669-3681
Number of pages13
JournalBiochemistry
Volume56
Issue number28
DOIs
StatePublished - Jul 18 2017

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Actinin
Current density
Assays
Biotinylation
Dendritic Spines
Mutation
Flow cytometry
Long-Term Potentiation
HEK293 Cells
Medical problems
Hypoglycemia
Point Mutation
Small Interfering RNA
Neurons
Cardiac Arrhythmias
Flow Cytometry
Ions
Health
Electric potential

ASJC Scopus subject areas

  • Biochemistry

Cite this

α-Actinin Promotes Surface Localization and Current Density of the Ca2+ Channel CaV1.2 by Binding to the IQ Region of the α1 Subunit. / Tseng, Pang Yen; Henderson, Peter B.; Hergarden, Anne C.; Patriarchi, Tommaso; Coleman, Andrea M.; Lillya, Mark W.; Montagut-Bordas, Carlota; Lee, Boram; Hell, Johannes W; Horne, Mary C.

In: Biochemistry, Vol. 56, No. 28, 18.07.2017, p. 3669-3681.

Research output: Contribution to journalArticle

Tseng, PY, Henderson, PB, Hergarden, AC, Patriarchi, T, Coleman, AM, Lillya, MW, Montagut-Bordas, C, Lee, B, Hell, JW & Horne, MC 2017, 'α-Actinin Promotes Surface Localization and Current Density of the Ca2+ Channel CaV1.2 by Binding to the IQ Region of the α1 Subunit', Biochemistry, vol. 56, no. 28, pp. 3669-3681. https://doi.org/10.1021/acs.biochem.7b00359
Tseng, Pang Yen ; Henderson, Peter B. ; Hergarden, Anne C. ; Patriarchi, Tommaso ; Coleman, Andrea M. ; Lillya, Mark W. ; Montagut-Bordas, Carlota ; Lee, Boram ; Hell, Johannes W ; Horne, Mary C. / α-Actinin Promotes Surface Localization and Current Density of the Ca2+ Channel CaV1.2 by Binding to the IQ Region of the α1 Subunit. In: Biochemistry. 2017 ; Vol. 56, No. 28. pp. 3669-3681.
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AU - Henderson, Peter B.

AU - Hergarden, Anne C.

AU - Patriarchi, Tommaso

AU - Coleman, Andrea M.

AU - Lillya, Mark W.

AU - Montagut-Bordas, Carlota

AU - Lee, Boram

AU - Hell, Johannes W

AU - Horne, Mary C

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