Yorimitsu Tomohiro, Zaman Shadia, Broach James R, Klionsky Daniel J
Life Sciences Institute, Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
Mol Biol Cell. 2007 Oct;18(10):4180-9. doi: 10.1091/mbc.e07-05-0485. Epub 2007 Aug 15.
Autophagy is a highly conserved, degradative process in eukaryotic cells. The rapamycin-sensitive Tor kinase complex 1 (TORC1) has a major role in regulating induction of autophagy; however, the regulatory mechanisms are not fully understood. Here, we find that the protein kinase A (PKA) and Sch9 signaling pathways regulate autophagy cooperatively in yeast. Autophagy is induced in cells when PKA and Sch9 are simultaneously inactivated. Mutant alleles of these kinases bearing a mutation that confers sensitivity to the ATP-analogue inhibitor C3-1'-naphthyl-methyl PP1 revealed that autophagy was induced independently of effects on Tor kinase. The PKA-Sch9-mediated autophagy depends on the autophagy-related 1 kinase complex, which is also essential for TORC1-regulated autophagy, the transcription factors Msn2/4, and the Rim15 kinase. The present results suggest that autophagy is controlled by the signals from at least three partly separate nutrient-sensing pathways that include PKA, Sch9, and TORC1.
自噬是真核细胞中一种高度保守的降解过程。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,其调控机制尚未完全明确。在此,我们发现蛋白激酶A(PKA)和Sch9信号通路在酵母中协同调节自噬。当PKA和Sch9同时失活时,细胞中会诱导自噬。这些激酶的突变等位基因带有赋予对ATP类似物抑制剂C3-1'-萘基甲基PP1敏感的突变,结果显示自噬的诱导独立于对Tor激酶的影响。PKA-Sch9介导的自噬依赖于自噬相关1激酶复合物,该复合物对TORC1调节的自噬、转录因子Msn2/4以及Rim15激酶也至关重要。目前的结果表明,自噬受至少三条部分独立的营养感应信号通路控制,这些通路包括PKA、Sch9和TORC1。