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Identification of obscure yet conserved actin associated proteins in Giardia lamblia.

TitleIdentification of obscure yet conserved actin associated proteins in Giardia lamblia.
Publication TypeJournal Article
Year of Publication2014
AuthorsParedez AR, Nayeri A, Xu JW, Krtkov√° J, Cande ZW
JournalEukaryotic cell
Date Published2014 Apr 11

Consistent with its proposed status as an early branching eukaryote, Giardia has the most divergent actin of any eukaryote and lacks core actin regulators. While conserved actin-binding proteins are missing from Giardia, its actin is utilized similarly to that of other eukaryotes and functions in core cellular processes such as cellular organization, endocytosis, and cytokinesis. We set out to identify actin-binding proteins in Giardia using affinity purification coupled with mass spectroscopy (Multi-Dimensional Protein Identification Technology, MudPIT) and have identified over 80 putative actin-binding proteins. Several of these have homology to conserved proteins known to complex with actin for functions in the nucleus and flagella. We validated localization and interaction for seven of these proteins including 14-3-3, a known cytoskeletal regulator with a controversial relationship to actin. Our results indicate that while Giardia lacks canonical actin-binding proteins, there is a conserved set of actin-interacting proteins that are evolutionarily indispensable and perhaps represent some of the earliest functions of the actin cytoskeleton.

Alternate JournalEukaryotic Cell