B-50/GAP-43 binds to actin filaments without affecting actin polymerization and filament organization

Jacques J H Hens, Fabio Benfenati, Henk B. Nielander, Flavia Valtorta, Willem Hendrik Gispen, Pierre N E De Graan

Research output: Contribution to journalArticlepeer-review


To investigate a possible function of the nervous tissue-specific protein kinase C substrate B-50/GAP-43 in regulation of the dynamics of the submembranous cytoskeleton, we studied the interaction between purified B-50 and actin. Both the phosphorylated and dephosphorylated forms of B-50 cosedimented with filamentous actin (F-actin) in a Ca2+-independent manner. Neither B-50 nor phospho-B-50 had any effect on the kinetics of actin polymerization and on the critical concentration at steady state, as measured using pyrenylated actin. Light scattering of F-actin samples was not increased in the presence of B-50, suggesting that B-50 does not bundle actin filaments. The number of actin filaments, determined by [3H]cytochalasin B binding, was not affected by either phospho- or dephospho-B-50, indicating that B-50 has neither a severing nor a capping effect. These observations were confirmed by electron microscopic evaluation of negatively stained F-actin samples, which did not reveal any structural changes in the actin meshwork on addition of B-50. We conclude that B-50 is an actin-binding protein that does not directly affect actin dynamics.

Original languageEnglish
Pages (from-to)1530-1533
Number of pages4
JournalJournal of Neurochemistry
Issue number4
Publication statusPublished - Oct 1993


  • Actin
  • Actin-bindinq proteins
  • B-50/GAP-43
  • Cytoskeleton
  • Protein kinase C

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


Dive into the research topics of 'B-50/GAP-43 binds to actin filaments without affecting actin polymerization and filament organization'. Together they form a unique fingerprint.

Cite this