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Glucose‐6‐Phosphate Dehydrogenase Interacts with Cav1.2 and Regulates [Ca2+]i in Coronary Artery Smooth Muscle
Author(s) -
Gupte Rakhee S,
Kurebayashi Naomi,
Gupte Sachin A
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb549
Subject(s) - chemistry , contraction (grammar) , caveolae , western blot , hek 293 cells , immunoprecipitation , myocyte , stimulation , microbiology and biotechnology , medicine , biophysics , receptor , endocrinology , signal transduction , biology , biochemistry , gene
G6PD plays a role in promoting contraction of coronary artery (CA); however, the molecular mechanism underlying this observation is still elusive. We have investigated the mechanism through which G6PD may regulate [Ca 2+ ] i in CA. We performed Western blot analysis of different cell fractions of CA and found that G6PD and Cav 1.2 co‐eluted with caveolin 1, suggesting that G6PD and Cav 1.2 co‐localized in the caveolae fraction. Hence, we hypothesized that G6PD may be involved in regulating [Ca 2+ ] i by interacting with Cav 1.2 . We performed co‐immunoprecipitation experiments and found that G6PD interacted with Cav 1.2 in resting coronary artery smooth muscle cells (CASMC) and CA. Interestingly, stimulation of CASMC and CA with KCl (30 mM), U46619 (100 nM) or PDBu (10 μM) increased G6PD‐Cav 1.2 complex. Furthermore, we co‐expressed human cardiac GFP‐fused‐Cav 1.2 and RFP‐fused‐G6PD in HEK 293T17 cells. FRET analysis confirmed their interaction in vivo with an efficiency of 0.47±0.05. To determine the implication of their interaction on CA function, we silenced G6PD in CA by siRNA resulting in decreased KCl‐induced increases in [Ca 2+ ] i and contraction of CA. Moreover, ectopic expression of G6PD in CA enhanced KCl (30 mM)‐evoked increases in [Ca 2+ ] i and contraction by 2‐ or 3‐fold as compared to control CA. These results, therefore, provide novel findings that G6PD interacts with Cav 1.2 , and suggest that G6PD & NADPH redox promotes CA contraction by elevating [Ca 2+ ] i , at least partly, through regulating L‐type Ca 2+ channel function. (Support by NIH grant HL085352)