Immunological evidence that HMG‐CoA reductase kinase‐A is the cauliflower homologue of the RKIN1 subfamily of plant protein kinases

Ball, Kathryn L.; Barker, J. H. A.; Halford, Nigel G.; Hardie, D. Grahame

doi:10.1016/0014-5793(95)01343-1

Cited by 49 publications

(36 citation statements)

References 25 publications

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“…Although the plant kinase was not purified to homogeneity, the catalytic subunit was identified using [ 14 C]FSBA labeling as a polypeptide of 58 kDa (61), the mass predicted for higher-plant Snf1 homologues. Antibodies raised against a sequence that is conserved in the plant Snf1 homologues cross-reacted with this polypeptide (63). These results strongly suggest that cauliflower HRK-A is encoded by a homologue of rye RKIN1 and yeast SNF1.…”

Section: Snf1-related Protein Kinases In Higher Plantssupporting

confidence: 53%

THE AMP-ACTIVATED/SNF1 PROTEIN KINASE SUBFAMILY: Metabolic Sensors of the Eukaryotic Cell?

Hardie

Carling

Carlson

1998

Annu. Rev. Biochem.

1,362

1,347

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Mammalian AMP-activated protein kinase and yeast SNF1 protein kinase are the central components of kinase cascades that are highly conserved between animals, fungi, and plants. The AMP-activated protein kinase cascade acts as a metabolic sensor or "fuel gauge" that monitors cellular AMP and ATP levels because it is activated by increases in the AMP:ATP ratio. Once activated, the enzyme switches off ATP-consuming anabolic pathways and switches on ATP-producing catabolic pathways, such as fatty acid oxidation. The SNF1 complex in yeast is activated in response to the stress of glucose deprivation. In this case the intracellular signal or signals have not been identified; however, SNF1 activation is associated with depletion of ATP and elevation of AMP. The SNF1 complex acts primarily by inducing expression of genes required for catabolic pathways that generate glucose, probably by triggering phosphorylation of transcription factors. SNF1-related protein kinases in higher plants are likely to be involved in the response of plant cells to environmental and/or nutritional stress.

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Section: Snf1-related Protein Kinases In Higher Plantssupporting

confidence: 53%

THE AMP-ACTIVATED/SNF1 PROTEIN KINASE SUBFAMILY: Metabolic Sensors of the Eukaryotic Cell?

Hardie

Carling

Carlson

1998

Annu. Rev. Biochem.

1,362

1,347

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“…In addition to the SAMS peptide, it phosphorylated and inactivated mammalian acetyl-CoA carboxylase and HMG-CoA reductase [ 1321, and it recognized a very similar sequence motif to AMPK and SNFI [46, 471. Its properties during purification (including native size) were very similar to AMPK, it was inactivated by treating with protein phosphatases, and could be reactivated by incubation with ATP and mammalian AMPKK [131]. The plant kinase has a catalytic subunit of 58 kDa, exactly as predicted by the sequences of the plant SNF1-related DNAs [132]. An antipeptide antibody raised against the rye and barley SNFl-related-kinase sequences cross-reacts with this 58-kDa polypeptide [ 1331.…”

Section: Functions Of Ampk -Related Protein Kinases In Yeast and Highmentioning

confidence: 92%

The AMP‐Activated Protein Kinase

Hardie

Carling

1997

European Journal of Biochemistry

1,255

1,055

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A single entity, the AMP-activated protein kinase (AMPK), phosphorylates and regulates in vivo hydroxymethylglutraryl-CoA reductase and acetyl-CoA carboxylase (key regulatory enzymes of sterol synthesis and fatty acid synthesis, respectively), and probably many additional targets, The kinase is activated by high AMP and low ATP via a complex mechanism, which involves allosteric regulation, promotion of phosphorylation by an upstream protein kinase (AMPK kinase), and inhibition of dephosphorylation. This protein-kinase cascade represents a sensitive system, which is activated by cellular stresses that deplete ATP, and thus acts like a cellular fuel gauge. Our central hypothesis is that, when it detects a 'low-fuel' situation, it protects the cell by switching off ATP-consuming pathways (e.g. fatty acid synthesis and sterol synthesis) and switching on alternative pathways for ATP generation (e.g. fatty acid oxidation). Native AMP-activated protein kinase is a heterotrimer consisting of a catalytic a subunit, and / 3 and y subunits, which are also essential for activity. All three subunits have homologues in budding yeast, which are components of the SNFl protein-kinase complex. SNFl is activated by glucose starvation (which in yeast leads to ATP depletion) and genetic studies have shown that it is involved in derepression of glucose-repressed genes. This raises the intriguing possibility that AMPK may regulate gene expression in mammals. AMPWSNFI homologues are found in higher plants, and this protein-kinase cascade appears to be an ancient system which evolved to protect cells against the effects of nutritional or environmental stress.

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“…Several soluble kinases have been partially purified from spinach leaf and cauliflower inflorescences that are able to inactivate SPS, NR, and HMR in vitro by phosphorylation on specific Ser residues (McMichael et al, 1993;Dale et al, 1995a;Douglas et al, 1997). Further analysis showed that some of these kinases were in fact homologs of the yeast SNF1 kinase and mammalian AMP-activated protein kinase, both of which limit the activity of specific metabolic pathways during stress by phosphorylation of regulatory enzymes such as HMR (Ball et al, 1995;Dale et al, 1995b;Sugden et al, 1999). Sequence alignments around the known regulatory phosphorylation sites of spinach SPS (Ser-158), spinach NR (Ser-543), and Arabidopsis HMR (Ser-577) from numerous species revealed several conserved residues (McMichael et al, 1993;Dale et al, 1995a;Douglas et al, 1997).…”

Section: Features Of the Putative Substrate Phosphorylation Sitementioning

confidence: 99%

Recombinant Brassinosteroid Insensitive 1 Receptor-Like Kinase Autophosphorylates on Serine and Threonine Residues and Phosphorylates a Conserved Peptide Motif in Vitro

Oh¹,

Ray²,

et al. 2000

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BRASSINOSTEROID-INSENSITIVE 1 (BRI1) encodes a putative Leucine-rich repeat receptor kinase in Arabidopsis that has been shown by genetic and molecular analysis to be a critical component of brassinosteroid signal transduction. In this study we examined some of the biochemical properties of the BRI1 kinase domain (BRI1-KD) in vitro, which might be important predictors of in vivo function. Recombinant BRI1-KD autophosphorylated on serine (Ser) and threonine (Thr) residues with p-Ser predominating. Matrix-assisted laser desorption/ionization mass spectrometry identified a minimum of 12 sites of autophosphorylation in the cytoplasmic domain of BRI1, including five in the juxtamembrane region (N-terminal to the catalytic KD), five in the KD (one each in sub-domains I and VIa and three in sub-domain VIII), and two in the carboxy terminal region. Five of the sites were uniquely identified (Ser-838, Thr-842, Thr-846, Ser-858, and Thr-872), whereas seven were localized on short peptides but remain ambiguous due to multiple Ser and/or Thr residues within these peptides. The inability of an active BRI1-KD to transphosphorylate an inactive mutant KD suggests that the mechanism of autophosphorylation is intramolecular. It is interesting that recombinant BRI1-KD was also found to phosphorylate certain synthetic peptides in vitro. To identify possible structural elements required for substrate recognition by BRI1-KD, a series of synthetic peptides were evaluated, indicating that optimum phosphorylation of the peptide required R or K residues at P Ϫ 3, P Ϫ 4, and P ϩ 5 (relative to the phosphorylated Ser at P ϭ 0).

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Immunological evidence that HMG‐CoA reductase kinase‐A is the cauliflower homologue of the RKIN1 subfamily of plant protein kinases

Cited by 49 publications

References 25 publications

THE AMP-ACTIVATED/SNF1 PROTEIN KINASE SUBFAMILY: Metabolic Sensors of the Eukaryotic Cell?

THE AMP-ACTIVATED/SNF1 PROTEIN KINASE SUBFAMILY: Metabolic Sensors of the Eukaryotic Cell?

The AMP‐Activated Protein Kinase

Recombinant Brassinosteroid Insensitive 1 Receptor-Like Kinase Autophosphorylates on Serine and Threonine Residues and Phosphorylates a Conserved Peptide Motif in Vitro

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