Calcium binding is essential for plastin 3 function in Smn-deficient motoneurons

Lyon, A.N., Pineda, R.H., Hao, L.T., Kudryashova, E., Kudryashov, D.S., and Beattie, C.E.
Human molecular genetics   23(8): 1990-2004 (Journal)
Registered Authors
Beattie, Christine, Pineda, Ricardo
MeSH Terms
  • Actinin/genetics
  • Actinin/metabolism*
  • Actins/metabolism
  • Animals
  • Blotting, Western
  • Calcium/metabolism
  • Cells, Cultured
  • Cofilin 1/genetics
  • Cofilin 1/metabolism*
  • Fluorescent Antibody Technique
  • HEK293 Cells
  • Humans
  • Membrane Glycoproteins/genetics
  • Membrane Glycoproteins/metabolism*
  • Microfilament Proteins/genetics
  • Microfilament Proteins/metabolism*
  • Motor Neurons/cytology
  • Motor Neurons/metabolism*
  • Muscular Atrophy, Spinal/genetics
  • Muscular Atrophy, Spinal/metabolism*
  • Muscular Atrophy, Spinal/pathology
  • Neuromuscular Junction/metabolism
  • Neuromuscular Junction/pathology
  • Phenotype
  • Profilins/genetics
  • Profilins/metabolism*
  • RNA, Messenger/genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • SMN Complex Proteins/deficiency*
  • SMN Complex Proteins/genetics
  • Zebrafish/genetics
  • Zebrafish/growth & development
  • Zebrafish/metabolism
24271012 Full text @ Hum. Mol. Genet.

The actin-binding and bundling protein, plastin 3 (PLS3), was identified as a protective modifier of spinal muscular atrophy (SMA) in some patient populations and as a disease modifier in animal models of SMA. How it functions in this process, however, is not known. Because PLS3 is an actin-binding/bundling protein, we hypothesized it would likely act via modification of the actin cytoskeleton in axons and neuromuscular junctions to protect motoneurons in SMA. To test this, we examined the ability of other known actin cytoskeleton organizing proteins to modify motor axon outgrowth phenotypes in an smn morphant zebrafish model of SMA. While PLS3 can fully compensate for low levels of smn, cofilin 1, profilin 2 and α-actinin 1 did not affect smn morphant motor axon outgrowth. To determine how PLS3 functions in SMA, we generated deletion constructs of conserved PLS3 structural domains. The EF hands were essential for PLS3 rescue of smn morphant phenotypes, and mutation of the Ca2+-binding residues within the EF hands resulted in a complete loss of PLS3 rescue. These results indicate that Ca2+ regulation is essential for the function of PLS3 in motor axons. Remarkably, PLS3 mutants lacking both actin-binding domains were still able to rescue motor axons in smn morphants, although not as well as full-length PLS3. Therefore, PLS3 function in this process may have an actin-independent component.

Genes / Markers
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes