PT  - JOURNAL ARTICLE
AU  - Barker, JHA.
AU  - Slocombe, S. P.
AU  - Ball, K. L.
AU  - Hardie, D. G.
AU  - Shewry, P. R.
AU  - Halford, N. G.
TI  - Evidence That Barley 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase Kinase Is a Member of the Sucrose Nonfermenting-1-Related Protein Kinase Family
AID  - 10.1104/pp.112.3.1141
DP  - 1996 Nov 01
TA  - Plant Physiology
PG  - 1141--1149
VI  - 112
IP  - 3
4099  - http://www.plantphysiol.org/content/112/3/1141.short
4100  - http://www.plantphysiol.org/content/112/3/1141.full
SO  - Plant Physiol.1996 Nov 01; 112
AB  - A protein kinase was partially purified from barley (Hordeum vulgare L. cv Sundance) endosperm by ammonium sulfate fractionation, followed by ion-exchange, Reactive Blue, Mono-Q, and phosphocellulose chromatography. It was shown to phosphorylate Arabidopsis 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and a synthetic peptide that was shown previously to act as a substrate for HMG-CoA reductase kinase purified from cauliflower, confirming it to be barley HMG-CoA reductase kinase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the partially purified preparation showed the presence of a polypeptide with an approximate relative molecular weight (Mr) of 60,000, which is the size predicted for the barley sucrose nonfermenting-1 (SNF1)-related protein kinases BKIN2 and BKIN12. Antisera were raised to a rye (Secale cereale L.) SNF1-related protein kinase (RKIN1) expressed in Escherichia coli as a fusion with maltose-binding protein and to a synthetic peptide with a sequence that is conserved in, and specific to, plant members of the SNF1-related protein kinase family. The maltose-binding protein-RKIN1 fusion protein antiserum recognized a doublet of polypeptides with an approximate Mr of 60,000 in crude endosperm extracts and a single polypeptide in root extracts, which co-migrated with the smaller polypeptide in the endosperm doublet. Both antisera recognized a polypeptide with an approximate Mr of 60,000 in the partially purified protein kinase preparation, suggesting strongly that barley HMG-CoA reductase kinase is a member of the SNF1-related protein kinase family.