Molecular modeling and deletion mutagenesis implicate the nuclear translocation sequence in structural integrity of fibroblast growth factor-1

Yongde Luo, Jerome L. Gabriel, Fen Wang, Xi Zhan, Thomas Maciag, Mikio Kan, Wallace L. McKeehan

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The sequence NYKKPKL in the NH2 terminus of fibroblast growth factor (FGF)-1 has been proposed to affect the long term activities of FGF-1 through its function as a nuclear translocation signal or its role in stabilization of the structure required to sustain binding and activation of the transmembrane receptor kinase. A dynamic molecular model of FGF-1 docked into a duplex of the FGF receptor ectodomain and a hexadecameric heparin chain suggests that the NYKKPKL sequence does not directly interact with heparin or the receptor, but rather the lysine-leucine residues within the sequence indirectly stabilize a major receptor-binding domain. Concurrent with a marked increase in dependence on exogenous heparin for optimal activity, sequential deletion of residues in the NYKKPKL sequence in FGF-1 resulted in a progressive loss of thermal stability, resistance to protease, mitogenic activity, and affinity for the transmembrane receptor. The largest change resulted from deletion of the entire sequence through the lysine-leucine residues. In the presence of sufficiently high concentrations of heparin, the deletion mutants exhibited mitogenic activity equal to wild-type FGF-1. The results confirm that a primary role of the NYKKPKL sequence domain is to maintain the structural integrity of FGF-1 required for optimal binding to and activation of the heparan sulfate-transmembrane receptor complex.

Original languageEnglish (US)
Pages (from-to)26876-26883
Number of pages8
JournalJournal of Biological Chemistry
Volume271
Issue number43
DOIs
StatePublished - 1996

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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