Fodrin in centrosomes: implication of a role of fodrin in the transport of gamma-tubulin complex in brain

PLoS One. 2013 Oct 1;8(10):e76613. doi: 10.1371/journal.pone.0076613. eCollection 2013.

Abstract

Gamma-tubulin is the major protein involved in the nucleation of microtubules from centrosomes in eukaryotic cells. It is present in both cytoplasm and centrosome. However, before centrosome maturation prior to mitosis, gamma-tubulin concentration increases dramatically in the centrosome, the mechanism of which is not known. Earlier it was reported that cytoplasmic gamma-tubulin complex isolated from goat brain contains non-erythroid spectrin/fodrin. The major role of erythroid spectrin is to help in the membrane organisation and integrity. However, fodrin or non-erythroid spectrin has a distinct pattern of localisation in brain cells and evidently some special functions over its erythroid counterpart. In this study, we show that fodrin and γ-tubulin are present together in both the cytoplasm and centrosomes in all brain cells except differentiated neurons and astrocytes. Immunoprecipitation studies in purified centrosomes from brain tissue and brain cell lines confirm that fodrin and γ-tubulin interact with each other in centrosomes. Fodrin dissociates from centrosome just after the onset of mitosis, when the concentration of γ-tubulin attains a maximum at centrosomes. Further it is observed that the interaction between fodrin and γ-tubulin in the centrosome is dependent on actin as depolymerisation of microfilaments stops fodrin localization. Image analysis revealed that γ-tubulin concentration also decreased drastically in the centrosome under this condition. This indicates towards a role of fodrin as a regulatory transporter of γ-tubulin to the centrosomes for normal progression of mitosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics
  • Actins / metabolism
  • Animals
  • Astrocytes / cytology
  • Astrocytes / metabolism
  • Brain / cytology
  • Brain / growth & development
  • Brain / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Line, Tumor
  • Centrosome / metabolism*
  • Centrosome / ultrastructure
  • Cytoplasm / metabolism*
  • Cytoplasm / ultrastructure
  • Embryo, Mammalian
  • Gene Expression Regulation, Developmental
  • Humans
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Mitosis*
  • Neural Stem Cells / cytology
  • Neural Stem Cells / metabolism*
  • Neurons / cytology
  • Neurons / metabolism
  • Primary Cell Culture
  • Protein Transport
  • Spindle Apparatus / metabolism
  • Spindle Apparatus / ultrastructure
  • Tubulin / genetics
  • Tubulin / metabolism*

Substances

  • Actins
  • Carrier Proteins
  • Microfilament Proteins
  • Tubulin
  • fodrin

Grants and funding

This work was supported by RGCB core funding and University Grants Commission, Government of India for fellowships to S. Shashikala (F. No. 10-2(5)/2006(i)-E.U.II.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.