The p150-Spir protein provides a link between c-Jun N-terminal kinase function and actin reorganization

Curr Biol. 2000 Mar 23;10(6):345-8. doi: 10.1016/s0960-9822(00)00388-2.


The Jun N-terminal kinase (JNK) is a downstream effector of Rac and Cdc42 GTPases involved in actin reorganization [1-3]. A role of the Drosophila JNK homologue, Basket (DJNK/Bsk), in the regulation of cell shape changes and actin reorganization arises from its function in the process of dorsal closure [4-6]. One potential mechanism for induction of cytoskeletal changes by JNK is via transcriptional activation of the decapentaplegic gene (dpp, a member of the TGFbeta superfamily) [6]. A direct link between JNK signalling and actin organization has not yet been found, however. We have identified a novel DJNK-interacting protein, p150-Spir, that belongs to the Wiscott-Aldrich syndrome protein (WASP) homology domain 2 (WH2) family of proteins involved in actin reorganization [7] [8]. It is a multidomain protein with a cluster of four WH2 domains, a modified FYVE zinc-finger motif [9], and a DEJL motif, a docking site for JNK [10], at its carboxy-terminal end. In mouse fibroblasts, p150-Spir colocalized with F-actin and its overexpression induced clustering of filamentous actin around the nucleus. When coexpressed with p150-Spir in NIH 3T3 cells, JNK translocated to and colocalizes with p150-Spir at discrete spots around the nucleus. Carboxy-terminal sequences of p150-Spir were phosphorylated by JNK both in vitro and in vivo. We conclude that p150-Spir is a downstream target of JNK function and provides a direct link between JNK and actin organization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Actins / metabolism*
  • Amino Acid Sequence
  • Animals
  • Cells, Cultured
  • Drosophila Proteins*
  • Insect Proteins / genetics
  • Insect Proteins / metabolism*
  • JNK Mitogen-Activated Protein Kinases
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Mitogen-Activated Protein Kinase Kinases / metabolism*
  • Mitogen-Activated Protein Kinase Kinases / physiology
  • Mitogen-Activated Protein Kinases / metabolism
  • Mitogen-Activated Protein Kinases / physiology
  • Molecular Sequence Data
  • Phosphorylation


  • Actins
  • Drosophila Proteins
  • Insect Proteins
  • Microfilament Proteins
  • spir protein, Drosophila
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • Hep protein, Drosophila
  • Mitogen-Activated Protein Kinase Kinases

Associated data

  • GENBANK/AJ238876