A Complex Containing SNF1-Related Kinase (SnRK1) and Adenosine Kinase in Arabidopsis

Abstract

SNF1-related kinase (SnRK1) in plants belongs to a conserved family that includes sucrose non-fermenting 1 kinase (SNF1) in yeast and AMP-activated protein kinase (AMPK) in animals. These kinases play important roles in the regulation of cellular energy homeostasis and in response to stresses that deplete ATP, they inhibit energy consuming anabolic pathways and promote catabolism. Energy stress is sensed by increased AMP:ATP ratios and in plants, 5′-AMP inhibits inactivation of phosphorylated SnRK1 by phosphatase. In previous studies, we showed that geminivirus pathogenicity proteins interact with both SnRK1 and adenosine kinase (ADK), which phosphorylates adenosine to generate 5′-AMP. This suggested a relationship between SnRK1 and ADK, which we investigate in the studies described here. We demonstrate that SnRK1 and ADK physically associate in the cytoplasm, and that SnRK1 stimulates ADK in vitro by an unknown, non-enzymatic mechanism. Further, altering SnRK1 or ADK activity in transgenic plants altered the activity of the other kinase, providing evidence for in vivo linkage but also revealing that in vivo regulation of these activities is complex. This study establishes the existence of SnRK1-ADK complexes that may play important roles in energy homeostasis and cellular responses to biotic and abiotic stress.

The circadian clock gene circuit controls protein and phosphoprotein rhythms inArabidopsis thaliana

“…In addition, the activating kinases of SnRK1, SnAK1 and SnAK2 (Crozet et al, 2010) and other members of the family auto-phosphorylate, some of them very slowly, like KaiC (Oh et al, 2012;Iwasaki et al, 2002;Nemoto et al, 2015). Like AMPK (Oakhill et al, 2011;Gowans et al, 2013) and SNF-1 (Mayer et al, 2011), SnRK1 is regulated by adenylates as it is protected by AMP from dephosphorylation by PP2C in vitro (Sugden et al, 1999) and interacts with adenosine kinase (Mohannath et al, 2014). Adenylates have previously been suggested as NTO components in an alga (Goto et al, 1985).…”

Regulation of Sucrose non-Fermenting Related Kinase 1 genes in Arabidopsis thaliana

“…The Arabidopsis SnRK1.2 gene has been overexpressed in N. benthamiana , where overexpression leads to enhanced resistance to geminiviral infection, although at the cost of adverse effects on plant growth (Mohannath et al, 2014). Although the network of genes regulated by SnRK1 has been elucidated (Baena-Gonzalez et al, 2007), our understanding of how the SnRK1.1 and SnRK1.2 genes themselves are regulated and function with respect to one another has not been addressed.…”

Transcriptome analyses provide insights into the phylogeny and adaptive evolution of the mangrove fern genus Acrostichum

“…This gene could improve the abiotic stress resistance via the regulation of abscisic acid signal transduction39, contribute to cytokinin-regulated leaf initiation40, and participate in photomorphogenesis by regulating the signaling of cell cycle41. The 27 PSGs in the lineage of A. aureum include AtBAG4 (Bcl-2-associated athanogene 4), an anti-apoptotic gene that significantly enhances the salt tolerance of rice42; adenylate kinase (ADK), a kinases of the SnRK1-ADK complexes that participates managing biotic and abiotic stresses and maintaining energy homeostasis43; and phosphomannomutase (PMM), which is required for the GDP-mannose biosynthesis, ascorbic acid biosynthesis and N-glycosylation and plays an important role in temperature adaptability4445. Of the 31 PSGs in the A. speciosum lineage, two are involved in the response to light.…”