Dynamic protrusions mediate unique crawling motility in Asgard Archaea (Promethearchaeota)
This article has been Reviewed by the following groups
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
- Evaluated articles (Arcadia Science)
Abstract
Crawling motility is a hallmark of eukaryotic cells and requires a dynamic actin cytoskeleton, regulated adhesion, and spatially organized signalling pathways 1–3 . Asgard archaea (phylum Promethearchaeota) which are considered the closest known prokaryotic relatives of eukaryotes potentially encode these functions within their large set of ‘eukaryotic signature proteins’ 4–9 . The few cultivated members show a complex cell morphology, consisting of a central cell body from which several protrusions extend, filled with an actin-based cytoskeleton 10,11 . Here, live cell microscopy of two organisms of the Loki- and Hodarchaea lineages 10,12 showed that they dynamically and drastically change their cell shape on a minute time scale and grow and retract their extensive protrusions with a speed of 1.5 to 5.3 µm/min, respectively. After adhering to a glass surface, cells employ their protrusions to undergo active crawling motion. In the presence of selected actin inhibitors however, the observed dynamics were arrested, suggesting a central role of actin in these processes. The observed cellular plasticity and motility are unique features among prokaryotes and might have been crucial for the emergence of the first eukaryotic cells that are thought to have formed through the association of a member of the Promethearchaeota and an alphaproteobacterium, the ancestor of mitochondria.
Article activity feed
-
Discussion
This is a really cool and thorough study and enjoyable to read detailing a system that’s rarely explored. Thanks for sharing!
-
While some commonly used inhibitors affected the dynamics or morphology only slightly, we found three inhibitors (Aspochalasin D, Chaetoglobosin A and Swinholide A) to significantly reduce the number of L. ossiferum cells adherent to glass (Fig. 3d, S3e, Supplementary table 1).
Fascinating screen showing how ineffective many common actin inhibitors can be in a non-traditional system, and how essential it is to have a diverse toolkit of compounds with different chemistries, binding affinities, and environmental stabilities. It really highlights that inhibitors developed for eukaryotic actin behave very differently in Lokiactin-based cells, and that relying on a single ‘standard’ drug would have missed most of the biology.
-
Upon coating the glass with poly-L-lysine, we found a decrease in both the protrusion dynamics and the migration speed (Fig. S2d-g), suggesting an intricate interplay between adhesion and detachment from the substrate to allow efficient cell migration31.
Related to the poly-L-lysine experiments in Fig. S2, did you ever see protrusions actually breaking off or being left behind on the surface at higher poly-L-lysine concentrations, or was the main effect just a slowdown in protrusion dynamics and cell migration? And did stronger adhesion noticeably change protrusion length distributions—for example, by increasing retraction/catastrophe events or biasing protrusions toward shorter lengths?
-
Fig. S1a).
Does the "Round" phenotype include Bulbs and Complex Arms? or just Bulbs?
-
