Phosphoinositides differentially regulate α-actinin flexibility and function

Anne Marie Corgan, Coreyayne Singleton, Cynthia B. Santoso, Jeffrey A. Greenwood

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

α-Actinin is a cell-adhesion and cytoskeletal protein that bundles actin microfilaments and links these filaments directly to integrin-adhesion receptors. Phosphoinositides bind to and regulate the interaction of α-actinin with actin filaments and integrin receptors. In the present study, we demonstrate that PtdIns(3,4,5)P3 inhibits and disrupts α-actinin-bundling activity, whereas PtdIns(4,5)P2 can only inhibit activity. In addition, a protease-sensitivity assay was developed to examine the flexibility of the linker region between the actin-binding domain and the spectrin repeats of α-actinin. Both phosphoinositides influenced the extent of proteolysis and the cleavage sites. PtdIns(4,5)P2 binding decreased the proteolysis of α-actinin, suggesting a role in stabilizing the structure of the protein. In contrast, PtdIns(SAS)P3 binding enhanced α-actinin proteolysis, indicating an increase in the flexibility of the protein. Furthermore, phosphoinositide binding influenced the proteolysis of the N- and C-terminal domains of α-actinin, indicating regulation of structure within both domains. These results support the hypothesis that PtdIns(4,5)P2 and PtdIns(SAS)P3 differentially regulate α-actinin function by modulating the structure and flexibility of the protein.

Original languageEnglish (US)
Pages (from-to)1067-1072
Number of pages6
JournalBiochemical Journal
Volume378
Issue number3
DOIs
StatePublished - Mar 15 2004
Externally publishedYes

Fingerprint

Actinin
Phosphatidylinositols
Proteolysis
Phosphatidylinositol 4,5-Diphosphate
Actins
Actin Cytoskeleton
Integrins
Spectrin
Proteins
Cytoskeletal Proteins
Cell adhesion
Cell Adhesion
Assays
Peptide Hydrolases

Keywords

  • α-actinin
  • Actin bundling
  • Cytoskeleton
  • Focal adhesion
  • Phosphoinositide
  • Protein flexibility

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Phosphoinositides differentially regulate α-actinin flexibility and function. / Corgan, Anne Marie; Singleton, Coreyayne; Santoso, Cynthia B.; Greenwood, Jeffrey A.

In: Biochemical Journal, Vol. 378, No. 3, 15.03.2004, p. 1067-1072.

Research output: Contribution to journalArticle

Corgan, Anne Marie ; Singleton, Coreyayne ; Santoso, Cynthia B. ; Greenwood, Jeffrey A. / Phosphoinositides differentially regulate α-actinin flexibility and function. In: Biochemical Journal. 2004 ; Vol. 378, No. 3. pp. 1067-1072.
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