Structural studies of arthrin: monoubiquitinated actin

S Burgess, M Walker, PJ Knight, J Sparrow, S Schmitz, GW Offer, B Bullard, K Leonard, J Holt, J Trinick

Research output: Contribution to journalArticle (Academic Journal)peer-review

19 Citations (Scopus)


Here, we report on the structure and in situ location of arthrin (monoubiquitinated actin). Labelling of insect muscle thin filaments with a ubiquitin antibody reveals that every seventh subunit along the filament long-pitch helices is ubiquitinated. A three-dimensional reconstruction of frozen-hydrated arthrin filaments was produced. This was based on a novel algorithm that divides filament images into short segments that are used for single-particle image processing. Difference maps with an actin filament reconstruction locate ubiquitin at the side of actin sub-domain 1 opposite where myosin binds. Consistent with the reconstructions, peptide mapping places the ubiquitin linkage on lysine 118 in actin. Molecular modelling was used to generate arthrin monomers from ubiquitin and actin crystal structures. Filament models constructed from these monomers were compared with the arthrin reconstruction. The reconstruction suggests ubiquitin attached to Lys118 adopts one or a few conformers, stabilized by a small interface with actin. The function of actin ubiquitination is not known, but may involve regulation of muscle contractile activity.
Translated title of the contributionStructural studies of arthrin: monoubiquitinated actin
Original languageEnglish
Pages (from-to)1161 - 1173
Number of pages13
JournalJournal of Molecular Biology
Volume341 (5)
Publication statusPublished - Aug 2004

Bibliographical note

Publisher: Academic Press


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