PMID- 16648185
OWN - NLM
STAT- MEDLINE
DCOM- 20061109
LR  - 20211020
IS  - 0363-6135 (Print)
IS  - 0363-6135 (Linking)
VI  - 291
IP  - 4
DP  - 2006 Oct
TI  - L-type calcium channel alpha-subunit and protein kinase inhibitors modulate 
      Rem-mediated regulation of current.
PG  - H1959-71
AB  - Cardiac voltage-gated L-type Ca channels (Ca(V)) are multiprotein complexes, 
      including accessory subunits such as Ca(V)beta2 that increase current expression. 
      Recently, members of the Rad and Gem/Kir-related family of small GTPases have 
      been shown to decrease current, although the mechanism remains poorly defined. In 
      this study, we evaluated the contribution of the L-type Ca channel alpha-subunit 
      (Ca(V)1.2) to Ca(V)beta2-Rem inhibition of Ca channel current. Specifically, we 
      addressed whether protein kinase A (PKA) modulation of the Ca channel modifies 
      Ca(V)beta2-Rem inhibition of Ca channel current. We first tested the effect of 
      Rem on Ca(V)1.2 in human embryonic kidney 293 (HEK-293) cells using the whole 
      cell patch-clamp configuration. Rem coexpression with Ca(V)1.2 reduces Ba current 
      expression under basal conditions, and Ca(V)beta2a coexpression enhances Rem 
      block of Ca(V)1.2 current. Surprisingly, PKA inhibition by 133 nM H-89 or 50 
      microM Rp-cAMP-S partially relieved the Rem-mediated inhibition of current 
      activity both with and without Ca(V)beta2a. To test whether the H-89 action was a 
      consequence of the phosphorylation status of Ca(V)1.2, we examined Rem regulation 
      of the PKA-insensitive Ca(V)1.2 serine 1928 (S1928) to alanine mutation 
      (Ca(V)1.2-S1928A). Ca(V)1.2-S1928A current was not inhibited by Rem and when 
      coexpression with Ca(V)beta2a was not completely blocked by Rem coexpression, 
      suggesting that the phosphorylation of S1928 contributes to Rem-mediated Ca 
      channel modulation. As a model for native Ca channel complexes, we tested the 
      ability of Rem overexpression in HIT-T15 cells and embryonic ventricular myocytes 
      to interfere with native current. We find that native current is also sensitive 
      to Rem block and that H-89 pretreatment relieves the ability of Rem to regulate 
      Ca current. We conclude that Rem is capable of regulating L-type current, that 
      release of Rem block is modulated by cellular kinase pathways, and that the 
      Ca(V)1.2 COOH terminus contributes to Rem-dependent channel inhibition.
FAU - Crump, Shawn M
AU  - Crump SM
AD  - Dept. of Physiology, MS-508, Univ. of Kentucky College of Medicine, 800 Rose St. 
      Lexington, KY 40536-0298, USA.
FAU - Correll, Robert N
AU  - Correll RN
FAU - Schroder, Elizabeth A
AU  - Schroder EA
FAU - Lester, William C
AU  - Lester WC
FAU - Finlin, Brian S
AU  - Finlin BS
FAU - Andres, Douglas A
AU  - Andres DA
FAU - Satin, Jonathan
AU  - Satin J
LA  - eng
GR  - R01 HL072936-03/HL/NHLBI NIH HHS/United States
GR  - HL-072936/HL/NHLBI NIH HHS/United States
GR  - HL-074091/HL/NHLBI NIH HHS/United States
GR  - R01 HL072936/HL/NHLBI NIH HHS/United States
GR  - P-20RR20171/RR/NCRR NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20060428
PL  - United States
TA  - Am J Physiol Heart Circ Physiol
JT  - American journal of physiology. Heart and circulatory physiology
JID - 100901228
RN  - 0 (Calcium Channels, L-Type)
RN  - 0 (Isoquinolines)
RN  - 0 (L-type calcium channel alpha(1C))
RN  - 0 (Protein Kinase Inhibitors)
RN  - 0 (Rem protein, mouse)
RN  - 0 (Sulfonamides)
RN  - 0 (Thionucleotides)
RN  - 23645-17-2 (adenosine-3',5'-cyclic phosphorothioate)
RN  - E0399OZS9N (Cyclic AMP)
RN  - EC 2.7.11.11 (Cyclic AMP-Dependent Protein Kinases)
RN  - EC 3.6.5.2 (Monomeric GTP-Binding Proteins)
RN  - M876330O56 (N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium Channels, L-Type/*drug effects/genetics/*physiology
MH  - Cell Line
MH  - Cricetinae
MH  - Cyclic AMP/analogs & derivatives/pharmacology
MH  - Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors/physiology
MH  - Gene Expression Regulation/physiology
MH  - Humans
MH  - Isoquinolines/pharmacology
MH  - Mesocricetus
MH  - Mice
MH  - Mice, Inbred ICR
MH  - Monomeric GTP-Binding Proteins/genetics/*metabolism/physiology
MH  - Myocytes, Cardiac/metabolism/physiology
MH  - Patch-Clamp Techniques
MH  - Phosphorylation
MH  - Protein Kinase Inhibitors/*pharmacology
MH  - Sulfonamides/pharmacology
MH  - Thionucleotides/pharmacology
EDAT- 2006/05/02 09:00
MHDA- 2006/11/11 09:00
CRDT- 2006/05/02 09:00
PHST- 2006/05/02 09:00 [pubmed]
PHST- 2006/11/11 09:00 [medline]
PHST- 2006/05/02 09:00 [entrez]
AID - 00956.2005 [pii]
AID - 10.1152/ajpheart.00956.2005 [doi]
PST - ppublish
SO  - Am J Physiol Heart Circ Physiol. 2006 Oct;291(4):H1959-71. doi: 
      10.1152/ajpheart.00956.2005. Epub 2006 Apr 28.