Sperm Associated Antigen 6 (SPAG6) Regulates Fibroblast Cell Growth, Morphology, Migration and Ciliogenesis

Sci Rep. 2015 Nov 20;5:16506. doi: 10.1038/srep16506.


Mammalian Spag6 is the orthologue of Chlamydomonas PF16, which encodes a protein localized in the axoneme central apparatus, and regulates flagella/cilia motility. Most Spag6-deficient mice are smaller in size than their littermates. Because SPAG6 decorates microtubules, we hypothesized that SPAG6 has other roles related to microtubule function besides regulating flagellar/cilia motility. Mouse embryonic fibroblasts (MEFs) were isolated from Spag6-deficient and wild-type embryos for these studies. Both primary and immortalized Spag6-deficient MEFs proliferated at a much slower rate than the wild-type MEFs, and they had a larger surface area. Re-expression of SPAG6 in the Spag6-deficient MEFs rescued the abnormal cell morphology. Spag6-deficient MEFs were less motile than wild-type MEFs, as shown by both chemotactic analysis and wound-healing assays. Spag6-deficient MEFs also showed reduced adhesion associated with a non-polarized F-actin distribution. Multiple centrosomes were observed in the Spag6-deficient MEF cultures. The percentage of cells with primary cilia was significantly reduced compared to the wild-type MEFs, and some Spag6-deficient MEFs developed multiple cilia. Furthermore, SPAG6 selectively increased expression of acetylated tubulin, a microtubule stability marker. The Spag6-deficient MEFs were more sensitive to paclitaxel, a microtubule stabilizer. Our studies reveal new roles for SPAG6 in modulation of cell morphology, proliferation, migration, and ciliogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • CHO Cells
  • COS Cells
  • Cell Adhesion / genetics
  • Cell Movement / genetics*
  • Cell Proliferation / genetics*
  • Cell Survival / genetics
  • Chlorocebus aethiops
  • Cilia / genetics*
  • Cilia / metabolism
  • Cricetinae
  • Cricetulus
  • Cytoskeleton / metabolism
  • Embryo, Mammalian / cytology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism*
  • Fibroblasts / ultrastructure
  • Mice, Knockout
  • Microscopy, Confocal
  • Microscopy, Electron, Scanning
  • Microtubule Proteins / genetics*
  • Microtubule Proteins / metabolism
  • Paclitaxel / pharmacology
  • Tubulin / metabolism
  • Tubulin Modulators / pharmacology


  • Microtubule Proteins
  • SPAG6 protein, mouse
  • Tubulin
  • Tubulin Modulators
  • Paclitaxel