Biology subjects

Strauskulage, L.

Publications and source records attributed to Strauskulage, L..

2 recordsLinked to original sources

bioRxiv2025

Archaeal SegAB forms a bipolar structure that promotes chromosome segregation in spherical cells

Archaeal segAB operons are thought to promote chromosome segregation, but their mechanism remains unknown. We employ comparative genomics, structural biology, genetic knockouts, and quantitative cell biology to investigate how SegA and SegB proteins work together to segregate chromosomes in the thermophilic archaeon Sulfolobus acidocaldarius. In vitro, SegB binds a centromeric DNA sequence adjacent to the segAB operon, and in vivo forms a distinct focus on each segregating chromosome. SegA, a ParA-like ATPase, binds DNA non-specifically in vitro and promotes chromosome compaction and segregation in vivo. During division, SegA shifts from chromosome-associated puncta to form a single, elongated figure that runs between separating SegB foci. Late in division, SegA retreats to regions surrounding separated SegB foci. Elongated SegA figures appear in segB knockout cells but no longer lie perpendicular to the division plane. We propose that SegA and SegB interact to form a bipolar, DNA-segregating structure radically different from bacterial ParABS systems.

cell biology↗

bioRxiv2020

DYRK2 is a ciliary kinase involved 1 in vertebrate Hedgehog signal transduction

Primary cilia are organelles specialized for signaling. We previously defined the proteomes of sea urchin and sea anemone cilia to identify ciliary proteins that predate the origin of bilateria. This evolutionary perspective on cilia identified DYRK2, a kinase not been previously implicated in ciliary biology. We found that DYRK2 localizes to cilia and that loss of DYRK2 disrupts ciliary morphology. We also found that DYRK2 participates in ciliary Hh signal transduction, communicating between SMO and GLI transcription factors. Mutation of mouse Dyrk2 resulted in skeletal defects reminiscent of those caused by loss of Indian hedgehog (Ihh). Like Dyrk2 mutations, pharmacological inhibition of DYRK2 dysregulates ciliary length control and attenuates Hedgehog signaling. Thus, DYRK2 is required for ciliary morphology, for Hedgehog signaling in vitro, and for skeletal development. We propose that DYRK2 is part of the mechanism that transduces SMO to activate GLI transcription factors within cilia.

developmental biology↗