TY - JOUR

T1 - Identification of ischemia-regulated phosphorylation sites in connexin43: A possible target for the antiarrhythmic peptide analogue rotigaptide (ZP123).

AU - Axelsen, Lene Nygaard

AU - Stahlhut, Martin

AU - Mohammed, Shabaz

AU - Larsen, Bjarne Due

AU - Nielsen, Morten S

AU - Andersen, Søren

AU - Jensen, Ole N

AU - Hennan, James K

AU - Kjølbye, Anne Louise

AU - Holstein-Rathlou, N.-H.

N1 - Keywords: Amino Acid Sequence; Animals; Connexin 43; Heart Arrest; Male; Molecular Sequence Data; Myocardial Ischemia; Oligopeptides; Phosphorylation; Phosphotransferases; Rats; Rats, Sprague-Dawley; Serine

PY - 2006

Y1 - 2006

N2 - Previous studies suggest that dephosphorylation of connexin43 (Cx43) is related to uncoupling of gap junction communication, which plays an important role in the genesis of ischemia-induced ventricular tachycardia. We studied changes in Cx43 phosphorylation during global ischemia in the absence and presence of the antiarrhythmic peptide analogue rotigaptide (formerly known as ZP123). Phosphorylation analysis was performed on Cx43 purified from isolated perfused rat hearts using matrix-assisted laser desorption/ionization mass spectrometry and liquid chromatography electrospray ionization tandem mass spectrometry. Thirteen different serine phosphorylation sites were identified in Cx43 during non-ischemic conditions, three of which had not previously been described. Within the first 7 min of ischemia, Ser306 became fully dephosphorylated whereas Ser330 became phosphorylated. Between 15 and 30 min of ischemia, the critical time interval where gap junction uncoupling occurs, Ser297 and Ser368 also became fully dephosphorylated. During the same time period, all untreated hearts developed asystole. Treatment with rotigaptide significantly increased the time to ischemia-induced asystole and suppressed dephosphorylation of Ser297 and Ser368 at 30 min of ischemia. Our results suggest that phosphorylation of Ser297 and Ser368 may be involved in functional gating of Cx43 during ischemia and may be possible downstream targets for rotigaptide signaling.

AB - Previous studies suggest that dephosphorylation of connexin43 (Cx43) is related to uncoupling of gap junction communication, which plays an important role in the genesis of ischemia-induced ventricular tachycardia. We studied changes in Cx43 phosphorylation during global ischemia in the absence and presence of the antiarrhythmic peptide analogue rotigaptide (formerly known as ZP123). Phosphorylation analysis was performed on Cx43 purified from isolated perfused rat hearts using matrix-assisted laser desorption/ionization mass spectrometry and liquid chromatography electrospray ionization tandem mass spectrometry. Thirteen different serine phosphorylation sites were identified in Cx43 during non-ischemic conditions, three of which had not previously been described. Within the first 7 min of ischemia, Ser306 became fully dephosphorylated whereas Ser330 became phosphorylated. Between 15 and 30 min of ischemia, the critical time interval where gap junction uncoupling occurs, Ser297 and Ser368 also became fully dephosphorylated. During the same time period, all untreated hearts developed asystole. Treatment with rotigaptide significantly increased the time to ischemia-induced asystole and suppressed dephosphorylation of Ser297 and Ser368 at 30 min of ischemia. Our results suggest that phosphorylation of Ser297 and Ser368 may be involved in functional gating of Cx43 during ischemia and may be possible downstream targets for rotigaptide signaling.

U2 - 10.1016/j.yjmcc.2006.03.005

DO - 10.1016/j.yjmcc.2006.03.005

M3 - Journal article

C2 - 16678851

VL - 40

SP - 790

EP - 798

JO - Journal of Molecular and Cellular Cardiology

JF - Journal of Molecular and Cellular Cardiology

SN - 0022-2828

IS - 6

ER -