Role of protein kinase Czeta and its adaptor protein p62 in voltage-gated potassium channel modulation in pulmonary arteries.
Voltage-gated potassium (K(V)) channels play an essential role in regulating pulmonary artery function, and they underpin the phenomenon of hypoxic pulmonary vasoconstriction. Pulmonary hypertension is characterized by inappropriate vasoconstriction, vascular remodeling, and dysfunctional K(V) channels. In the current study, we aimed to elucidate the role of PKCzeta and its adaptor protein p62 in the modulation of K(V) channels. We report that the thromboxane A(2) analog 9,11-dideoxy-11alpha,9alpha-epoxymethano-prostaglandin F(2alpha) methyl acetate (U46619) inhibited K(V) currents in isolated mice pulmonary artery myocytes and the K(V) current carried by human cloned K(V)1.5 channels expressed in Ltk(-) cells. Using protein kinase C (PKC)zeta(-/-) and p62(-/-) mice, we demonstrate that these two proteins are involved in the K(V) channel inhibition. PKCzeta coimmunoprecipitated with K(V)1.5, and this interaction was markedly reduced in p62(-/-) mice. Pulmonary arteries from PKCzeta(-/-) mice also showed a diminished [Ca(2+)](i) and contractile response, whereas genetic inactivation of p62(-/-) resulted in an absent [Ca(2+)](i) response, but it preserved contractile response to U46619. These data demonstrate that PKCzeta and its adaptor protein p62 play a key role in the modulation of K(V) channel function in pulmonary arteries. These observations identify PKCzeta and/or p62 as potential therapeutic targets for the treatment of pulmonary hypertension.
Moreno
Laura
L
Department of Pharmacology, School of Medicine, Universidad Complutense, 28040 Madrid, Spain.
Frazziano
Giovanna
G
Cogolludo
Angel
A
Cobeño
Laura
L
Tamargo
Juan
J
Perez-Vizcaino
Francisco
F
D000818:Animals; D020013:Calcium Signaling; D051666:Kv1.5 Potassium Channel / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011651:Pulmonary Artery / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013928:Thromboxane A2 / Q000494:pharmacology; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014661:Vasoconstriction / Q000235:genetics; D000099221:Protein Kinase C zeta
D051666:Kv1.5 Potassium Channel; D011493:Protein Kinase C; D013928:Thromboxane A2; D051758:Transcription Factor TFIIH; D014157:Transcription Factors; D000099221:Protein Kinase C zeta; C490981:Gtf2h1 protein, mouse