Phosphorylation of basic fibroblast growth factor (FGF‐2) in the nuclei of SK‐Hep‐1 cells

FEBS Letters

Gonzalez, Ana Maria¹  Vilgrain, Isabelle¹  Baird, Andrew¹ 

[1] Department of Molecular and Cellular Growth Biology, The Whittier Institute for Diabetes and Endocrinology, 9894 Genesee Avenue, La Jolla, CA 92037, USA

关键词: Growth factor;    Nucleus;    Kinase;    Phosphorylation;    FGF;    SK-Hep cell;   

DOI  :  10.1016/0014-5793(93)80342-R

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The subcellular fractions containing protein kinases capable of phosphorylating basic fibroblast growth factor (FGF-2) are unknown, but having previously characterized one that is associated with the plasma membrane [1991, Mol. Endocrinol. 5, 1003-1012] we evaluated the catalytic properties of another in the nucleus. The reaction is time (linear up to 15 min), enzyme (2,000–25,000 nuclei/ml), and substrate (K _m, 0.18 μM) dependent, and the targets serine. DNase pretreatment of nuclei decreases the incorporation of phosphate into FGF-2 by 50% and the reaction. It is also inhibited by heparin (EC₅₀ 1 μg/ml) and spermidine (EC₅₀3μM). Calcium and cAMP have no effect. We conclude that the kinase is distinct from PKA, and PKC, and suggest that changes in glycosaminoglycan and polyamine concentrations during the cell cycle may modulate FGF-2 phosphorylation in the nucleus, or as it is translocated to the nucleus.

【 授权许可】

Unknown