Yorimitsu Tomohiro, He Congcong, Wang Ke, Klionsky Daniel J
Life Sciences Institute, Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, USA.
Autophagy. 2009 Jul;5(5):616-24. doi: 10.4161/auto.5.5.8091. Epub 2009 Jul 29.
Autophagy is a highly conserved degradative process in eukaryotic cells. This process plays an integral role in cellular physiology, and the levels of autophagy must be precisely controlled to prevent cellular dysfunction. The rapamycin-sensitive Tor kinase complex 1 (TORC1) has a major role in regulating the induction of autophagy; however, the regulatory mechanisms are not fully understood. Here, we find that Tap42 and protein phosphatase type 2A (PP2A) are involved in the regulation of autophagy in yeast. Temperature-sensitive mutant alleles of TAP42 revealed that autophagy was induced without inactivation of TORC1. Absence of the Tap42-interacting protein Tip41 abolished autophagy induction in the tap42 mutants, whereas overexpression of Tip41 activated autophagy. Furthermore, inactivation of PP2A stimulated autophagy and overexpression of a catalytic subunit of PP2A blocked rapamycin-induced autophagy. Our data support a model in which autophagy is negatively regulated by the Tap42-PP2A pathway.
自噬是真核细胞中一种高度保守的降解过程。该过程在细胞生理学中起着不可或缺的作用,自噬水平必须得到精确控制以防止细胞功能障碍。雷帕霉素敏感的Tor激酶复合物1(TORC1)在调节自噬诱导中起主要作用;然而,其调节机制尚未完全阐明。在这里,我们发现Tap42和2A型蛋白磷酸酶(PP2A)参与酵母自噬的调节。TAP42的温度敏感突变等位基因表明,在TORC1未失活的情况下自噬被诱导。Tap42相互作用蛋白Tip41的缺失消除了tap42突变体中的自噬诱导,而Tip41的过表达激活了自噬。此外,PP2A的失活刺激自噬,PP2A催化亚基的过表达阻断雷帕霉素诱导的自噬。我们的数据支持一种模型,即自噬受到Tap42-PP2A途径的负调控。