Insect fat body phosphorylase kinase is Ca2+-independent and acts even at 0 degrees C.
Fat body glycogen phosphorylase in some overwintering insects is known to be activated by cold and, therefore, this enzyme acts as a key enzyme that regulates the production of glycerol or trehalose from glycogen during winter. In this paper we report the mechanism of phosphorylase activation by cold: the major phosphorylase kinase (EC 2.7.1.38) of fat body is bound to glycogen and functions at 0 degrees C, whereas phosphorylase phosphatase does not; thus this may cause a slow but continuous accumulation of the active form of phosphorylase in the cold.
D000273:Adipose Tissue / Q000201:enzymology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent / Q000494:pharmacology; D003080:Cold Temperature; D005216:Fat Body / Q000201:enzymology*; D006003:Glycogen / Q000378:metabolism; D009036:Moths; D010764:Phosphorylase Kinase / Q000378:metabolism*
D002413:Cations, Divalent; D006003:Glycogen; D010764:Phosphorylase Kinase; D002118:Calcium