Fibroblast growth factor-1 interacts with the glucose-regulated protein GRP75/mortalin

E Mizukoshi, M Suzuki, A Loupatov, T Uruno, Hisaki Hayashi, Tomato Misono, S C Kaul, R Wadhwa, Toru Imamura

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83 Citations (Scopus)


Fibroblast growth factor-1 (FGF-1), which lacks a signal peptide and is intracellularly localized as a result of endogenous expression or endocytosis, is thought to be involved in regulating cell growth and differentiation. In the study reported here, we purified proteins that bind intracellular FGF-1. Affinity adsorption was used to purify FGF-1-binding proteins from rat L6 cells expressing FGF-1. One of the isolated proteins was identified as the glucose-regulated protein GRP75/mortalin/PBP-74/mthsp70, a member of the hsp70 family of heat-shock proteins known to be involved in regulating glucose responses, antigen processing and cell mortality. The interaction of FGF-1 and GRP75/mortalin in vivo was confirmed by co-immunoprecipitation, immunohistochemical co-localization in Rat-1 fibroblasts and by using the yeast two-hybrid system. Moreover, a binding assay in vitro with the use of recombinant FGF-1 and mortalin demonstrated a direct physical interaction between the two proteins. These results reveal that GRP75/mortalin is an intracellular FGF-1-binding protein in cells and suggest that GRP75/mortalin is involved in the trafficking of and/or signalling by FGF-1.

Original languageEnglish
Pages (from-to)461-6
Number of pages6
JournalThe Biochemical journal
Volume343 Pt 2
Publication statusPublished - Oct 15 1999


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