Calmyrin1 binds to SCG10 protein (stathmin2) to modulate neurite outgrowth

Biochim Biophys Acta. 2011 May;1813(5):1025-37. doi: 10.1016/j.bbamcr.2010.12.023. Epub 2011 Jan 6.


Calmyrin1 (CaMy1) is an EF-hand Ca(2+)-binding protein expressed in several cell types, including brain neurons. Using a yeast two-hybrid screen of a human fetal brain cDNA library, we identified SCG10 protein (stathmin2) as a CaMy1 partner. SCG10 is a microtubule-destabilizing factor involved in neuronal growth during brain development. We found increased mRNA and protein levels of CaMy1 during neuronal development, which paralleled the changes in SCG10 levels. In developing primary rat hippocampal neurons in culture, CaMy1 and SCG10 colocalized in cell soma, neurites, and growth cones. Pull-down, coimmunoprecipitation, and proximity ligation assays demonstrated that the interaction between CaMy1 and SCG10 is direct and Ca(2+)-dependent in vivo and requires the C-terminal domain of CaMy1 (residues 99-192) and the N-terminal domain of SCG10 (residues 1-35). CaMy1 did not interact with stathmin1, a protein that is homologous with SCG10 but lacks the N-terminal domain characteristic of SCG10. CaMy1 interfered with SCG10 inhibitory activity in a microtubule polymerization assay. Moreover, CaMy1 overexpression inhibited SCG10-mediated neurite outgrowth in nerve growth factor (NGF)-stimulated PC12 cells. This CaMy1 activity did not occur when an N-terminally truncated SCG10 mutant unable to interact with CaMy1 was expressed. Altogether, these data suggest that CaMy1 via SCG10 couples Ca(2+) signals with the dynamics of microtubules during neuronal outgrowth in the developing brain. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Calcium-Binding Proteins / chemistry
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Carrier Proteins / metabolism*
  • Cell Differentiation / drug effects
  • Gene Expression Regulation / drug effects
  • HeLa Cells
  • Hippocampus / cytology
  • Hippocampus / embryology
  • Humans
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Microtubule Proteins
  • Microtubules / drug effects
  • Microtubules / metabolism
  • Nerve Growth Factor / pharmacology
  • Neurites / drug effects
  • Neurites / metabolism*
  • PC12 Cells
  • Polymerization / drug effects
  • Protein Binding / drug effects
  • Protein Structure, Tertiary
  • Protein Transport / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Stathmin
  • Tubulin / metabolism


  • CIB1 protein, human
  • Calcium-Binding Proteins
  • Carrier Proteins
  • Cib1 protein, rat
  • Membrane Proteins
  • Microtubule Proteins
  • RNA, Messenger
  • STMN2 protein, human
  • Stathmin
  • Stmn2 protein, rat
  • Tubulin
  • Nerve Growth Factor
  • Calcium