. Author manuscript; available in PMC: 2017 Apr 15.

Published in final edited form as: Mol Cell Endocrinol. 2015 Dec 28;425:48–60. doi: 10.1016/j.mce.2015.12.006

Table 1.

IGFBP-1 peptide sequence (45-180) and possible phosphorylation sites for CK2, PKC and PKA.

IGFBP-1 sequence (45-180)
Protein Kinase	Consensus phosphorylation site motif sequence (X=any amino acid):	IGFBP-1 peptides with potential substrate sites	Validated by in vitro kinase assay
CK2	pS/T-X-X-D/E	*^p**S¹⁰¹TEITEEE pS¹¹⁹EED pS¹⁶⁹GEE	Validated Validated Validated
PKC	pS/T-X-R/K	pT⁵⁰ AR pS⁵⁸ CR	--
PKA	R/K-R/K-X-pS/T	pT⁵⁰AR pS⁵⁸CR	--

IGFBP-1 residues Ser101, Ser119 and Ser169 have been shown to be potential sites for phosphorylation by CK2 in HepG2 cells in response to leucine deprivation in vitro, in human FGR umbilical cord plasma from FGR pregnancies and in baboon FGR fetal liver from maternal nutrient restriction in vivo.

pSer101 is not a precise consensus sequence site for CK2. Conversely, PKC and PKA are not likely to directly phosphorylate IGFBP-1 at Ser 101, 119 and 169 sites.