Human 5'-amp-activated Protein Kinase Y <sub> 2 </ Sub> Isomers Of Molecular Cloning, Genomic Structure, Organization Expression Profiling Analysis On The Chromosome Positioning

5'-AMP-activated protein kinase (AMPK) acts as a main regulator of cellular ATP level and protects the cell from stresses that cause ATP depletion. It is well established that in normal cells there exists highly-active adenylate kinase which catalyzes the transition among ATP, ADP and AMP to maintain the ratio of [ATP]: [ADP]:[AMP] to 100:10:1. But in cases of low nutrition, normal or innormal physiological conditions that make cells consume most of their ATP conserve, AMPK would be activated by high ratio of [ATP]:[AMP] and then phosphorylates, inactivates its downstream enzymes, most of which are the key or speed-limit enzymes that could control the energy flow of metabolism, such as 3-hydroxy-3-methylglutary-coenzyme A reductase and acetyl-CoA carboxylase. When those enzymes are activated by AMPK, they would shut down the energy-consuming biosynthesis pathway and turn on the energy-producing fatty acid oxidation pathway. So the basic function of AMPK is to keep the minimal level of cellular ATP and protect the cell from apoptosis induced by low concertration of ATP. Now some researcher have also found evidences that AMPK was involved in transcription, apoptosis, Ca²⁺ /calmodulin system, Ras signal transduction system and endothelial NO synthase system.AMPK is a protein heterotrimer with one catalytic α subunit and two regulatory subunits( β and γ subunits). Up to now, two isoforms of α , β or γ subunits have been revealed respectively, but only one isoform of γ subunit have been found. It is important that the AMPKs composed with different isoforms of α or β subunit are of distinct functional characterization, for example, the heterotrimers containing...