Protein composition and movements of membrane swellings associated with primary cilia

Ashraf M. Mohieldin, Hanan S. Haymour, Shao T. Lo, Wissam A. Aboualaiwi, Kimberly F. Atkinson, Christopher J. Ward, Min Gao, Oliver Wessely, Surya M. Nauli

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Abstract Dysfunction of many ciliary proteins has been linked to a list of diseases, from cystic kidney to obesity and from hypertension to mental retardation. We previously proposed that primary cilia are unique communication organelles that function as microsensory compartments that house mechanosensory molecules. Here we report that primary cilia exhibit membrane swellings or ciliary bulbs, which based on their unique ultrastructure and motility, could be mechanically regulated by fluid-shear stress. Together with the ultrastructure analysis of the swelling, which contains monosialodihexosylganglioside (GM3), our results show that ciliary bulb has a distinctive set of functional proteins, including GM3 synthase (GM3S), bicaudal-c1 (Bicc1), and polycystin-2 (PC2). In fact, results from our cilia isolation demonstrated for the first time that GM3S and Bicc1 are members of the primary cilia proteins. Although these proteins are not required for ciliary membrane swelling formation under static condition, fluid-shear stress induced swelling formation is partially modulated by GM3S. We therefore propose that the ciliary bulb exhibits a sensory function within the mechano-ciliary structure. Overall, our studies provided an important step towards understanding the ciliary bulb function and structure.

Original languageEnglish (US)
Article number1838
Pages (from-to)2415-2429
Number of pages15
JournalCellular and Molecular Life Sciences
Issue number12
StatePublished - Jun 26 2015


  • Bicc-1
  • Ciliary bulb
  • Ciliary membrane swelling
  • Fluid-shear stress
  • GM3S
  • PC2
  • Primary cilia

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Pharmacology
  • Cellular and Molecular Neuroscience
  • Cell Biology


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