Ca(2+) sensors of L-type Ca(2+) channel.
Ca(2+)-induced inactivation of L-type Ca(2+) is differentially mediated by two C-terminal motifs of the alpha(1C) subunit, L (1572-1587) and K (1599-1651) implicated for calmodulin binding. We found that motif L is composed of a highly selective Ca(2+) sensor and an adjacent Ca(2+)-independent tethering site for calmodulin. The Ca(2+) sensor contributes to higher Ca(2+) sensitivity of the motif L complex with calmodulin. Since only combined mutation of both sites removes Ca(2+)-dependent current decay, the two-site modulation by Ca(2+) and calmodulin may underlie Ca(2+)-induced inactivation of the channel.
Romanin
C
C
Institute for Biophysics, University of Linz, Austria.
Gamsjaeger
R
R
Kahr
H
H
Schaufler
D
D
Carlson
O
O
Abernethy
D R
DR
Soldatov
N M
NM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D002147:Calmodulin / Q000378:metabolism*; D002460:Cell Line; D005982:Glutathione Transferase / Q000235:genetics; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
D020746:Calcium Channels, L-Type; D002147:Calmodulin; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D002118:Calcium