Fig. 3.

Activation of GYS1:GN1 by dephosphorylation. (A) GYS1:GN1 was incubated with buffer control (mock) or GST-PP1c as described in methods and glycosyltransferase activity determined using saturating UDP-glucose (4 mM) in the presence or absence of 10 mM G6P. Results represent mean ± SD for three independent experiments. (B) Activity ratio (−G6P/+10 mM G6P) for native (mock) and dephosphorylated (+PP1c) forms of GYS1:GN1. Results represent the mean ± SD for three independent experiments. (C) Analysis of the major regulatory phosphorylation sites on recombinant GYS1 by Western blotting of the preparations described in (A). Samples were denatured in Laemmli buffer and immunoblotted with the indicated antibodies. ^∗Cell Signaling anti-GYS1 (#3893). ^∗∗Santa Cruz anti-GYS1 (sc-81173, GS-7H5).