Author: Masayuki Onishi

New collaboration paper (Yaning Yuan): Alternative proteoforms and proteoform-dependent assemblies in humans and plants. in Mol Syst Biol

Masayuki Onishi

https://pubmed.ncbi.nlm.nih.gov/38918600/

See also: https://www.oeaw.ac.at/gmi/news-events/news-press/tracing-the-origin-of-truncated-protein-variants

Graduate Student Yaning Yuan took part in a collaboration with Claire McWhite (Princeton) and Silvia Ramundo (GMI Vienna) in the study that identified a large number of proteins showing alternative proteoforms. One of such proteins, fibrocystin/PKHD1 shows the same pattern of cleavage-dependent processing as in humans. Yaning is now studying the potential role of PKHD1 in cell division in both Chlamydomonas and humans. Stay tuned!

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

Masayuki Onishi

A new paper on cytokinesis in Chlamydomonas has been published in PNAS.
https://doi.org/10.1073/pnas.1920337117

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.