Hypoxia alters the subcellular distribution of protein kinase C isoforms in neonatal rat ventricular myocytes
Hypoxia alters the subcellular distribution of protein kinase C isoforms in neonatal rat ventricular myocytes
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DOI：
10.1172/jci119133
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发表时间：
1997-01-01
影响因子：
15.9
通讯作者：
Steinberg, SF
中科院分区：
文献类型：
--
作者：
Goldberg, M;Zhang, HL;Steinberg, SF
心肌细胞共表达多种蛋白激酶C（PKC）亚型，这些亚型可能在导致收缩力、肥大和缺血预适应变化的信号通路中发挥不同的作用。虽然PKC已被报道在心肌缺血期间被激活，但缺血/缺氧对单个PKC亚型的影响尚未确定。本研究探讨了缺氧对培养的新生大鼠心室肌细胞PKC亚型亚细胞分布的影响。缺氧诱导PKC α和PKC β从可溶性到颗粒隔室的重新分布。这种作用（推测代表PKC α和PKC β的活化）在1小时内可检测到，持续长达24小时，并且在复氧1小时内可逆。用三环癸-9-基-黄原酸酯（D 609）抑制磷脂酶C可防止缺氧诱导的PKC α和PKC β的再分布，而用1，2-双磷酸钙螯合细胞内钙，（2-氨基苯氧基）乙烷-N，N，N '，N'-四乙酸（BAPTA）阻断PKC α的再分布，但不阻断PKC β的再分布; D 609和BAPTA不影响常氧心肌细胞中PKC α和PKC β的分配。相比之下，缺氧通过与缺氧诱导的PKC α/PKC β易位/激活不同的机制降低PKC δ的膜结合，因为反应开始较慢，在复氧后缓慢可逆，并且不被D 609或BAPTA阻断。低氧诱导的PKC δ向可溶性隔室的转移并不能阻止随后的4-β佛波醇12-肉豆蔻酸酯-13-乙酸酯依赖性PKC δ的易位/激活。缺氧不改变任何PKC亚型的丰度，也不改变PKC λ的亚细胞分布。通过磷脂酶C（PKC α/PKC β）和细胞内钙（PKC α）的途径，选择性低氧诱导的PKC亚型的活化可能严重影响心肌细胞收缩性、基因表达和/或对缺血的耐受性。
Cardiac myocytes coexpress multiple protein kinase C (PKC) isoforms which likely play distinct roles in signaling pathways leading to changes in contractility, hypertrophy, and ischemic preconditioning. Although PKC has been reported to be activated during myocardial ischemia, the effect of ischemia/hypoxia on individual PKC isoforms has not been determined. This study examines the effect of hypoxia on the subcellular distribution of individual PKC isoforms in cultured neonatal rat ventricular myocytes. Hypoxia induces the redistribution of PKC alpha and PKC epsilon from the soluble to the particulate compartment. This effect (which is presumed to represent activation of PKC alpha and PKC epsilon) is detectable by 1 h, sustained for up to 24 h, and reversible within 1 h of reoxygenation. Inhibition of phospholipase C with tricyclodecan-9-yl-xanthogenate (D609) prevents the hypoxia-induced redistribution of PKC alpha and PKC epsilon, whereas chelation of intracellular calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) blocks the redistribution of PKC alpha, but not PKC epsilon; D609 and BAPTA do not influence the partitioning of PKC alpha and PKC epsilon in normoxic myocytes. Hypoxia, in contrast, decreases the membrane association of PKC delta via a mechanism that is distinct from the hypoxia-induced translocation/activation of PKC alpha/PKC epsilon, since the response is slower in onset, slowly reversible upon reoxygenation, and not blocked by D609 or BAPTA. The hypoxia-induced shift of PKC delta to the soluble compartment does not prevent subsequent 4-beta phorbol 12-myristate-13-acetate-dependent translocation/activation of PKC delta. Hypoxia does not alter the abundance of any PKC isoform nor does it alter the subcellular distribution of PKC lambda. The selective hypoxia-induced activation of PKC isoforms through a pathway involving phospholipase C (PKC alpha/PKC epsilon) and intracellular calcium (PKC alpha) may critically influence cardiac myocyte contractility, gene expression, and/or tolerance to ischemia.