Akt is an essential player in regulating cell/organ growth at the adult stage in the hard tick Haemaphysalis longicornis
Akt is an essential player in regulating cell/organ growth at the adult stage in the hard tick Haemaphysalis longicornis
复制标题
DOI：
10.1016/j.ibmb.2011.12.001
复制
发表时间：
2012-03-01
影响因子：
3.8
通讯作者：
Fujisaki, Kozo
中科院分区：
文献类型：
--
作者：
Umemiya-Shirafuji, Rika;Tanaka, Toru;Fujisaki, Kozo
蜱在吸血期间迅速生长，它们的体重最终可能比吸血前增加100倍。蜱在吸血期间控制生长的分子机制在很大程度上仍然未知。胰岛素/PI 3 K/Akt信号通路在真核生物中调节生长和代谢。在这里，我们显示的证据参与Akt的生长在血液喂养的孤雌生殖株硬蜱长角血蜱。我们从H.长角胚HlAkt cDNA具有1，590 bp的开放阅读框，编码529个氨基酸，预测分子量为60 kDa。HlAkt具有PH结构域、Ser/Thr激酶结构域、疏水基序和激酶活化所必需的双磷酸化残基（Thr 338和Ser 503）。通过RNA干扰敲低HlAkt引起雌性蜱的吸血抑制。组织学观察表明，HlAkt敲低导致内脏器官的生长停滞。HlAkt敲低也影响了血餐诱导的基因的表达，这些基因对雌性蜱的血液消化、发育和繁殖至关重要。这些结果强烈表明，HlAkt是必不可少的，以完成吸血过程伴随着内部器官的生长在成年蜱。这是首次在螯肢动物（包括蜱类）中鉴定和表征Akt的报告。(C)2011爱思唯尔有限公司版权所有。
Ticks grow rapidly during blood feeding, and their body weight may ultimately increase 100-fold more than that before feeding. The molecular mechanisms controlling growth during blood feeding in ticks remain largely unknown. The conserved insulin/PI3K/Akt signaling pathway regulates growth and metabolism in eukaryotes. Here, we show evidence for the involvement of Akt in growth during blood feeding in the parthenogenetic strain of the hard tick Haemaphysalis longicornis. We identified a homolog of the Ser/Thr kinase Akt (HlAkt) from the EST database of the H. longicornis embryo. HlAkt cDNA had a 1,590 bp ORF that encodes 529 amino acids with a predicted molecular weight of 60 kDa. HlAkt possesses a PH domain, a Ser/Thr kinase domain, a hydrophobic motif, and dual phosphorylation residues (Thr 338 and Ser 503) that are essential for kinase activation. Knockdown of HlAkt by RNA interference caused inhibition of blood feeding in female ticks. Histological observation demonstrated that HlAkt knockdown led to the arrest of growth in internal organs. HlAkt knockdown also affected the expressions of blood meal-induced genes that are essential for blood digestion, development, and reproduction in the female tick. These results strongly indicate that HlAkt is essential to complete the blood feeding process accompanied by the growth of internal organs in adult ticks. This is the first report of identification and characterization of Akt in Chelicerata, including ticks. (C) 2011 Elsevier Ltd. All rights reserved.