Phopshorylase kinase (PhK) is a hexadecameric holoenzyme made up of four different subunits in the arrangement (αβγδ)4 and has total molecular mass of 1.3MDa. Alpha and β are regulatory subunits, γ is catalytic, and δ is an intrinsic molecule of calmodulin. PhK is a serine threonine kinase with glycogenolytic regulatory functions. Our lab has recently discovered that the γ subunit can be alternatively processed to produce a truncated form of 181 residues (γ-181). This variant of γ contains a phosphorylation site for PK-C, and its activity is influenced by this phosphorylation. We are using a LexA based yeast two hybrid system to identify potential binding partners for γ-181. In the present study we are cloning the human γ-181 in to a Lex-A DNA binding domain vector to use as “bait” for screening a human brain c-DNA library. Interaction between γ-181 and the brain c-DNA library proteins will be monitored using LacZ and LEU2 as reporter genes. Library plasmids isolated from the clones that show positive results on the yeast two hybrid screen will be sequenced to identify novel binding partners for γ-181.
Dr. Nancy Rice
Polireddy, Kishore, "Searching for Binding Partners for the Novel PHKG1 Variant, PhKγ 181" (2008). Student Research Conference Select Presentations. Paper 9.