AMPK:不仅能感应细胞的能量状态还能感应葡萄糖

文章简介腺嘌呤核苷酸水平的改变,即AMP/ATP和ADP/ATP比值的上升是细胞能量状态下降的信号。众所周知,哺乳动物的AMPK会随细胞能量水平的下降而激活。这篇综述回顾了近来关于细胞的低能量状态如何激活AMPK的研究成果,同时还探讨了最近关于国家重点研发计划;;\n国家自然科学基金委项目的支

Similar substrate recognition motifs for mammalian AMP-activated protein kinase, higher plant HMG-CoA reductase kinase-A, yeast SNF1, and mammalian calmodulin-dependent protein kinase I

AbstractWe have analysed phosphorylation of the synthetic peptide AMARAASAAALARRR, and 23 variants, by mammalian, higher plant and yeast members of the SNF1 protein kinase subfamily (AMP-activated protein kinase (AMPK), HMG-CoA reductase kinase (HRK-A), and SNF1 itself), and by mammalian calmodulin-dependent protein kinase I (CaMKI). These four kinases recognize motifs which are very similar, although distinguishable. Our studies define the following recognition motifs: AMPK: Φ(X,β)XXS/TXXXΦ; HRK-A: Φ(X,β)XXSXXXΦ; Snf1: ΦXRXXSXXXΦ; CaMKI: ΦXRXXS/TXXXΦ; where Φ is a hydrophobic residue (M, V, L, I or F) and β is a basic residue (R, K or H)

Specificity determinants for the AMP-activated protein kinase and its plant homologue analysed using synthetic peptides

AbstractInspection of sequences around sites phosphorylated by the AMP-activated protein kinase (AMP-PK), and homologous sequences from other species, indicates conserved features. There are hydrophobic residues (M, V, L, I) at P-5 and P+4, and at least one basic residue (R, K, H) at P-2, P-3 or P-4. The importance of these residues has been established for AMP-PK and its putative plant homologue using a series of synthetic peptides. These results confirm the functional similarity of the animal and plant kinases, and suggest that the required motif for recognition of substrate by either kinase is M/V/L/I-(R/K/H,X,X)-X-S/T-X-X-X-M/V/L/I

A common bicyclic protein kinase cascade inactivates the regulatory enzymes of fatty acid and cholesterol biosynthesis

AbstractA highly purified rat liver protein kinase phosphorylates and inactivates acetyl-CoA carboxylase, and causes rapid inactivation of microsomal HMG-CoA reductase in the presence of MgATP. Both effects are stimulated in an identical manner by AMP, and are greatly reduced by prior treatment of the kinase with purified protein phosphatase. The dephosphorylated kinase can be reactivated in the presence of MgATP, apparently due to a distinct kinase kinase, and this reactivation is stimulated by nanomolar concentrations of palmitoyl-CoA. These results show that a common, bicyclic protein kinase cascade can potently inactivate the regulatory enzymes of both fatty acid and cholesterol biosynthesis

Identification of Raf-1 Ser621 kinase activity from NIH3T3 cells as AMP-activated protein kinase

AbstractRaf-1 is extensively phosphorylated on Ser621 in both quiescent and mitogen-stimulated cells. To identify the responsible kinase(s), cytosolic fractions of NIH3T3 cells were analyzed for Ser621 peptide kinase activity. One major peak of activity was detected and identified as AMP-activated protein kinase (AMPK) by immunodepletion experiments. AMPK phosphorylated the catalytic domain of Raf-1, expressed in Escherichia coli as a soluble GST fusion protein, to generate a single tryptic [32P]phosphopeptide containing exclusively phospho-Ser621. AMPK also phosphorylated full-length, kinase-defective Raf-1 (K375M) to generate two [32P]phosphopeptides, one co-migrating with synthetic tryptic peptide containing phospho-Ser621 and the other with phospho-Ser259.© Federation of European Biochemical Societies