Schematics of putative SIK-mediated phosphorylation sites on mouse
nSREBP-1c sequences. A, putative phosphorylation sites by SIK
kinases on mouse SREBP-1c nuclear form are shown. Each mutant construct is
designed as an alanine substitution for the serine residue indicated.
B, in vitro kinase assay was performed with purified
GST-fused nSREBP-1c proteins and immunoprecipitated FLAG-tagged SIK1. Effects
of specific alanine substitution mutations on SREBP-1c for SIK-induced
phosphorylation were shown. C, comparison of amino acid sequences for
nSREBP-1c within the SIK target region (serine 265/266 and serine 329) among
humans, mice, and rats. 3A, S265A/S266A/S329A.