TY - JOUR
T1 - Roscovitine binds to novel L-channel (Cav1.2) sites that separately affect activation and inactivation
AU - Yarotskyy, Viktor
AU - Gao, Guofeng
AU - Du, Lei
AU - Ganapathi, Sindura B.
AU - Peterson, Blaise Z.
AU - Elmslie, Keith S.
PY - 2010/1/1
Y1 - 2010/1/1
N2 - L-type (CaV1.2) calcium channel antagonists play an important role in the treatment of cardiovascular disease. (R)-Roscovitine, a trisubstituted purine, has been shown to inhibit L-currents by slowing activation and enhancing inactivation. This study utilized molecular and pharmacological approaches to determine whether these effects result from (R)-roscovitine binding to a single site. Using the S enantiomer, we find that (S)-roscovitine enhances inactivation without affecting activation, which suggests multiple sites. This was further supported in studies using chimeric channels comprised of N- and L-channel domains. Those chimeras containing L-channel domains I and IV showed (R)- roscovitine-induced slowed activation like that of wild type L-channels, whereas chimeric channels containing L-channel domain I responded to (R)-roscovitine with enhanced inactivation. We conclude that (R)-roscovitine binds to distinct sites on L-type channels to slow activation and enhance inactivation. These sites appear to be unique from other calcium channel antagonist sites that reside within domains III and IV and are thus novel sites that could be exploited for future drug development. Trisubstituted purines could become a new class of drugs for the treatment of diseases related to hyperfunction of L-type channels, such as Torsades de Pointes.
AB - L-type (CaV1.2) calcium channel antagonists play an important role in the treatment of cardiovascular disease. (R)-Roscovitine, a trisubstituted purine, has been shown to inhibit L-currents by slowing activation and enhancing inactivation. This study utilized molecular and pharmacological approaches to determine whether these effects result from (R)-roscovitine binding to a single site. Using the S enantiomer, we find that (S)-roscovitine enhances inactivation without affecting activation, which suggests multiple sites. This was further supported in studies using chimeric channels comprised of N- and L-channel domains. Those chimeras containing L-channel domains I and IV showed (R)- roscovitine-induced slowed activation like that of wild type L-channels, whereas chimeric channels containing L-channel domain I responded to (R)-roscovitine with enhanced inactivation. We conclude that (R)-roscovitine binds to distinct sites on L-type channels to slow activation and enhance inactivation. These sites appear to be unique from other calcium channel antagonist sites that reside within domains III and IV and are thus novel sites that could be exploited for future drug development. Trisubstituted purines could become a new class of drugs for the treatment of diseases related to hyperfunction of L-type channels, such as Torsades de Pointes.
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U2 - 10.1074/jbc.M109.076448
DO - 10.1074/jbc.M109.076448
M3 - Article
C2 - 19887376
AN - SCOPUS:73649111717
SN - 0021-9258
VL - 285
SP - 43
EP - 53
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 1
ER -