Cleavage-furrow formation without F-actin – new publication in PNAS

A new paper on cytokinesis in Chlamydomonas has been published in PNAS.

In this paper, we demonstrated that F-actin is enriched in the cleavege-furrow region of dividing Chlamydomonas cells by using Lifeact marker.  Interestingly, however, there is no myosin co-localizing with F-actin in the furrow, suggesting that no “actomyosin” structure is directly involved in furrowing.  Moreover, complete removal of F-actin by a combination of an actin toxin latrunculin B and a mutation in NAP1 (which encodes a latrunculin-resistant, unconventional actin – see our previous publications 1,2) did not completely block furrow ingression.  Because microtubules are still associated with the furrows formed in the absence of F-actin, we believe that this cytoskeleton plays a major role in cytokinesis, which may have been inherited from very early ancestors of eukaryotes, or even earlier ancestors shared with archaea and bacteria.

New on bioRxiv: Our paper on Furrowing without F-actin

Cleavage-furrow formation without F-actin in Chlamydomonas

Masayuki Onishi, James G Umen, Frederick R Cross, John R Pringle

Onishi Lab is Opening in January 2020!

We will investigate the fundamental core mechanisms of cytokinesis and their evolution from the common ancestors, using Chlamydomonas in our lab, and with collaborators who use other systems.  Join us for this exciting expedition!!

Septins, cytokinesis, and ER stress – Collaboration paper

A collaboration paper with Maho Niwa’s lab at UCSD on an intriguing behavior of the septin ring under ER stress has been published in Developmental Cell.