An image-based RNAi screen identifies SH3BP1 as a key effector of Semaphorin 3E-PlexinD1 signaling

J Cell Biol. 2014 May 26;205(4):573-90. doi: 10.1083/jcb.201309004. Epub 2014 May 19.


Extracellular signals have to be precisely interpreted intracellularly and translated into diverse cellular behaviors often mediated by cytoskeletal changes. Semaphorins are one of the largest families of guidance cues and play a critical role in many systems. However, how different cell types translate extracellular semaphorin binding into intracellular signaling remains unclear. Here we developed and performed a novel image-based genome-wide functional RNAi screen for downstream signaling molecules that convert the interaction between Semaphorin 3E (Sema3E) and PlexinD1 into cellular behaviors. One of the genes identified in this screen is a RhoGAP protein, SH3-domain binding protein 1 (SH3BP1). We demonstrate that SH3BP1 mediates Sema3E-induced cell collapse through interaction with PlexinD1 and regulation of Ras-related C3 botulinum toxin substrate 1 (Rac1) activity. The identification and characterization of SH3BP1 as a novel downstream effector of Sema3E-PlexinD1 provides an explanation for how extracellular signals are translated into cytoskeletal changes and unique cell behavior, but also lays the foundation for characterizing other genes identified from our screen to obtain a more complete picture of plexin signaling.

Publication types

  • Research Support, N.I.H., Extramural
  • Video-Audio Media

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Cell Adhesion Molecules, Neuronal / chemistry
  • Cell Adhesion Molecules, Neuronal / genetics
  • Cell Adhesion Molecules, Neuronal / metabolism*
  • Extracellular Space / metabolism
  • GTPase-Activating Proteins / chemistry
  • GTPase-Activating Proteins / genetics
  • GTPase-Activating Proteins / metabolism*
  • Genome-Wide Association Study
  • HEK293 Cells
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Membrane Glycoproteins
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • RNA Interference
  • Semaphorins / chemistry
  • Semaphorins / genetics
  • Semaphorins / metabolism*
  • Signal Transduction / physiology*
  • rac1 GTP-Binding Protein / metabolism


  • Cell Adhesion Molecules, Neuronal
  • GTPase-Activating Proteins
  • Intracellular Signaling Peptides and Proteins
  • Membrane Glycoproteins
  • PLXND1 protein, human
  • SEMA3E protein, human
  • SH3BP1 protein, human
  • Semaphorins
  • rac1 GTP-Binding Protein

Associated data

  • GENBANK/BC004598
  • GENBANK/NM015103