Targeting of a Tropomyosin Isoform to Short Microfilaments Associated with the Golgi Complex

Justin M. Percival, Julie A.I. Hughes, Darren L. Brown, Galina Schevzov, Kirsten Heimann, Bernadette Vrhovski, Nicole Bryce, Jennifer L. Stow, Peter W. Gunning

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

A growing body of evidence suggests that the Golgi complex contains an actin-based filament system. We have previously reported that one or more isoforms from the tropomyosin gene Tm5NM (also known as γ-Tm), but not from either the α- or β-Tm genes, are associated with Golgi-derived vesicles (Heimann et al., (1999). J. Biol. Chem. 274, 10743-10750). We now show that Tm5NM-2 is sorted specifically to the Golgi complex, whereas Tm5NM-1, which differs by a single alternatively spliced internal exon, is incorporated into stress fibers. Tm5NM-2 is localized to the Golgi complex consistently throughout the G1 phase of the cell cycle and it associates with Golgi membranes in a brefeldin A-sensitive and cytochalasin D-resistant manner. An actin antibody, which preferentially reacts with the ends of microfilaments, newly reveals a population of short actin filaments associated with the Golgi complex and particularly with Golgi-derived vesicles. Tm5NM-2 is also found on these short microfilaments. We conclude that an alternative splice choice can restrict the sorting of a tropomyosin isoform to short actin filaments associated with Golgi-derived vesicles. Our evidence points to a role for these Golgi-associated microfilaments in vesicle budding at the level of the Golgi complex.

Original languageEnglish (US)
Pages (from-to)268-280
Number of pages13
JournalMolecular biology of the cell
Volume15
Issue number1
DOIs
StatePublished - Jan 1 2004

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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    Percival, J. M., Hughes, J. A. I., Brown, D. L., Schevzov, G., Heimann, K., Vrhovski, B., Bryce, N., Stow, J. L., & Gunning, P. W. (2004). Targeting of a Tropomyosin Isoform to Short Microfilaments Associated with the Golgi Complex. Molecular biology of the cell, 15(1), 268-280. https://doi.org/10.1091/mbc.E03-03-0176