Two types of phosphofructokinase-1 differentially regulate the glycolytic pathway in insulin-stimulated chicken skeletal muscle.
To elucidate the precise regulation of glucose homeostasis in chicken skeletal muscle, expression of muscle- and liver-type phosphofructokinase-1 (EC:2.7.1.11, PFK-M, PFK-L) was characterized in the insulin-stimulated state by Real-Time PCR. Firstly, chicken PFK-M and PFK-L full-length cDNA sequences were identified. The deduced amino acid sequences were 81.6% and 86.5% identical with human PFK-M and PFK-L, respectively. In pectoralis superficialis (PS) muscle and extensor digitorum longus (EDL), PFK-M mRNA levels were unchanged following insulin stimulation. Surprisingly, although mammalian PFK-L has been reported to be expressed in liver, kidney and brain, chicken PFK-L was not detected in liver and kidney, however, strong expression was detected in skeletal muscle and brain by Northern blot analysis. However, using PCR, PFK-L mRNA was detected in liver. Taken together, chicken PFK-L mRNA expression was at a very low level, below the detection limit of Northern blot analysis. Chicken PFK-L mRNA levels were increased 200% in PS muscle but decreased by 40% in EDL following insulin stimulation. These results suggest that two types of PFK regulate the glycolytic pathway in the insulin-stimulated state and, therefore, that glucose metabolism in chicken skeletal muscle may be regulated in a very different manner compared to mammals.
Seki
Yoshinori
Y
Animal Nutrition, Division of Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan.
Sato
Kan
K
Kono
Tatsuyoshi
T
Akiba
Yukio
Y
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D003001:Cloning, Molecular; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis / Q000235:genetics; D007328:Insulin / Q000494:pharmacology; D008099:Liver / Q000737:chemistry; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology*; D025501:Phosphofructokinase-1, Liver Type / Q000235:genetics / Q000378:metabolism*; D025203:Phosphofructokinase-1, Muscle Type / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism
D007328:Insulin; D012333:RNA, Messenger; D025501:Phosphofructokinase-1, Liver Type; D025203:Phosphofructokinase-1, Muscle Type; D005947:Glucose