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An actin‐based cytoskeleton in archaea
Author(s) -
Ettema Thijs J. G.,
Lindås AnnChristin,
Bernander Rolf
Publication year - 2011
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2011.07635.x
Subject(s) - biology , cytoskeleton , cytokinesis , actin , microbiology and biotechnology , mreb , actin cytoskeleton , ftsz , cell division , cell , genetics
Summary In eukaryotic and bacterial cells, spatial organization is dependent upon cytoskeletal filaments. Actin is a main eukaryotic cytoskeletal element, involved in key processes such as cell shape determination, mechanical force generation and cytokinesis. We describe an archaeal cytoskeleton which forms helical structures within Pyrobaculum calidifontis cells, as shown by in situ immunostaining. The core components include an archaeal actin homologue, Crenactin, closely related to the eukaryotic counterpart. The crenactin gene belongs to a conserved gene cluster denoted Arcade ( a ctin‐ r elated c ytoskeleton in A rchaea involved in shape de termination). The phylogenetic distribution of arcade genes is restricted to the crenarchaeal Thermoproteales lineage, and to Korarchaeota, and correlates with rod‐shaped and filamentous cell morphologies. Whereas Arcadin‐1, ‐3 and ‐4 form helical structures, suggesting cytoskeleton‐associated functions, Arcadin‐2 was found to be localized between segregated nucleoids in a cell subpopulation, in agreement with possible involvement in cytokinesis. The results support a crenarchaeal origin of the eukaryotic actin cytoskeleton and, as such, have implications for theories concerning the origin of the eukaryotic cell.