Identification of a polyphosphoinositide-binding sequence in an actin monomer-binding domain of gelsolin

F. X. Yu, H. Q. Sun, P. A. Janmey, H. L. Yin

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13 Scopus citations


Gelsolin is an actin filament-severing and -capping protein that has profound effects on actin filament organization and assembly. It is activated by Ca2+ and inhibited by polyphosphoinositides (PPI). We have previously shown that PPI inhibit actin filament severing by the amino-terminal half of gelsolin and hypothesized that this is mediated through inhibition of actin filament side binding (by domains II-III of gelsolin), a requisite first step in severing. In this paper, we report that the subsequent step in severing, which is mediated by an actin monomer binding site located in domain I of gelsolin, is also regulated by PPI. We used deletional mutagenesis and a synthetic peptide to locate the sequence required for high affinity PPI binding in domain I. Our results show that the PPI-binding sequence has a basic charge distribution that is also present in the PPI-regulated actin filament side binding domain, and the two gelsolin PPI-binding sites have similar PPI-binding affinities. In addition, a similar motif is present in several other PPI-binding proteins, including a highly conserved region in the phospholipase C family. We propose that the sequences identified in gelsolin may represent a consensus for PPI binding in a variety of proteins.

Original languageEnglish (US)
Pages (from-to)14616-14621
Number of pages6
JournalJournal of Biological Chemistry
Issue number21
StatePublished - 1992

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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