Effect of bestrophin-1 on L-type Ca2+ channel activity depends on the Ca2+ channel beta-subunit.
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Effect of bestrophin-1 on L-type Ca2+ channel activity depends on the Ca2+ channel beta-subunit. / Reichhart, Nadine; Milenkovic, Vladimir M; Halsband, Claire-Amelie; Cordeiro, Sönke; Strauss, Olaf.
In: EXP EYE RES, Vol. 91, No. 5, 5, 2010, p. 630-639.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Effect of bestrophin-1 on L-type Ca2+ channel activity depends on the Ca2+ channel beta-subunit.
AU - Reichhart, Nadine
AU - Milenkovic, Vladimir M
AU - Halsband, Claire-Amelie
AU - Cordeiro, Sönke
AU - Strauss, Olaf
PY - 2010
Y1 - 2010
N2 - Best's vitelliforme macular degeneration is an inherited retinal degeneration associated with a reduction of the light-peak in the patient's electro-oculogram. Bestrophin-1, the product of the disease-promoting/forming gene can function as regulator of voltage-dependent L-type Ca(2+) channels in the retinal pigment epithelium (RPE). Since mice deficient for either 4-subunits or Ca(V)1.3 subunits show reduced light-peaks, the regulatory function of bestrophin-1 on heterologously expressed Ca(2+) channels composed of the pore-forming Ca(V)1.3 and the auxiliary 4-subunit was analyzed. Precipitation of 4-subunits led to co-precipitation with bestrophin-1 and subsequent analysis of subcellular localization showed co-localization of bestrophin-1, Ca(V)1.3 and 4-subunit in the cell membrane. Ca(V)1.3 currents in the presence of 4-subunits and bestrophin-1 showed accelerated time-dependent activation and decreased current density compared to currents measured in the absence of bestrophin-1. In the presence of the 3-subunit, which is not expressed in the RPE bestrophin-1 did not modulate Ca(V)1.3 activity. Deletion of a cluster of proline-rich motifs in the C-terminus of bestrophin-1 reduced its co-immuno precipitation with the 4-subunit and strongly reduced the Ca(V)1.3 activity. Cells co-expressing bestrophin-1 lacking the proline-rich motifs and Ca(V)1.3 subunits showed less efficient trafficking of bestrophin-1 into the cell membrane. In summary, we conclude that bestrophin-1 modulates L-type channels of the RPE via proline-rich motif-dependent interaction with 4-subunits. A disturbed interaction reduces the currents of the Ca(V)1.3 subunits. This mechanism could open new ways to understand changes in the patient's electro-oculogram and functional alterations of the RPE leading to retinal degeneration.
AB - Best's vitelliforme macular degeneration is an inherited retinal degeneration associated with a reduction of the light-peak in the patient's electro-oculogram. Bestrophin-1, the product of the disease-promoting/forming gene can function as regulator of voltage-dependent L-type Ca(2+) channels in the retinal pigment epithelium (RPE). Since mice deficient for either 4-subunits or Ca(V)1.3 subunits show reduced light-peaks, the regulatory function of bestrophin-1 on heterologously expressed Ca(2+) channels composed of the pore-forming Ca(V)1.3 and the auxiliary 4-subunit was analyzed. Precipitation of 4-subunits led to co-precipitation with bestrophin-1 and subsequent analysis of subcellular localization showed co-localization of bestrophin-1, Ca(V)1.3 and 4-subunit in the cell membrane. Ca(V)1.3 currents in the presence of 4-subunits and bestrophin-1 showed accelerated time-dependent activation and decreased current density compared to currents measured in the absence of bestrophin-1. In the presence of the 3-subunit, which is not expressed in the RPE bestrophin-1 did not modulate Ca(V)1.3 activity. Deletion of a cluster of proline-rich motifs in the C-terminus of bestrophin-1 reduced its co-immuno precipitation with the 4-subunit and strongly reduced the Ca(V)1.3 activity. Cells co-expressing bestrophin-1 lacking the proline-rich motifs and Ca(V)1.3 subunits showed less efficient trafficking of bestrophin-1 into the cell membrane. In summary, we conclude that bestrophin-1 modulates L-type channels of the RPE via proline-rich motif-dependent interaction with 4-subunits. A disturbed interaction reduces the currents of the Ca(V)1.3 subunits. This mechanism could open new ways to understand changes in the patient's electro-oculogram and functional alterations of the RPE leading to retinal degeneration.
KW - Animals
KW - Humans
KW - CHO Cells
KW - Cricetinae
KW - Cricetulus
KW - Amino Acid Sequence
KW - Molecular Sequence Data
KW - Calcium Channels metabolism
KW - Blotting, Western
KW - Patch-Clamp Techniques
KW - Protein Binding
KW - Basement Membrane metabolism
KW - Calcium Channels, L-Type metabolism
KW - Chloride Channels physiology
KW - Electrophoresis, Polyacrylamide Gel
KW - Eye Proteins physiology
KW - Immunoenzyme Techniques
KW - Kidney embryology
KW - Mutagenesis, Site-Directed
KW - Proline-Rich Protein Domains
KW - Retinal Pigment Epithelium metabolism
KW - Transduction, Genetic
KW - Animals
KW - Humans
KW - CHO Cells
KW - Cricetinae
KW - Cricetulus
KW - Amino Acid Sequence
KW - Molecular Sequence Data
KW - Calcium Channels metabolism
KW - Blotting, Western
KW - Patch-Clamp Techniques
KW - Protein Binding
KW - Basement Membrane metabolism
KW - Calcium Channels, L-Type metabolism
KW - Chloride Channels physiology
KW - Electrophoresis, Polyacrylamide Gel
KW - Eye Proteins physiology
KW - Immunoenzyme Techniques
KW - Kidney embryology
KW - Mutagenesis, Site-Directed
KW - Proline-Rich Protein Domains
KW - Retinal Pigment Epithelium metabolism
KW - Transduction, Genetic
M3 - SCORING: Zeitschriftenaufsatz
VL - 91
SP - 630
EP - 639
JO - EXP EYE RES
JF - EXP EYE RES
SN - 0014-4835
IS - 5
M1 - 5
ER -
