BIOM20001 Lecture Notes - Lecture 15: Glycogen Phosphorylase, Glycogen Synthase, Citric Acid Cycle
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Remember that f-2,6-bisp is an allosteric activator of pfk-1. if we shut down the kinase domain we favor the conversion of f-2,6-bisp to f-6-p which has negative regulatory effect on pfk-1. The regulation doesn"t affect fbpase-1 (gluconeogenesis) but inhibits a competing pathway. Inhibiting pk activity shuts down conversion of pep to pyruvate slowing the feed into. The gluconeogenesis pathway is still converting pyruvate into glucose. Want to down regulate glycogen synthase as this produces glycogen from glucose. Want to up regulate glycogen phosphorylase which breaks it down. The activated pka phosphorylates glycogen synthase which inhibits it. Pka also phosphorylates phosphorylase kinase which in turn phosphorylates glycogen phosphorylase which promotes its activity. Glycogen broken into g-1-p which then makes glucose. Pka translocates to the nucleus and phosphorylates creb protein. It binds to and upregulates genes which produce the protein pepck. Gtp into pep + gdp + co2 which then goes on to glucose (gng)
