Plastid translocon recycling in dinoflagellates demonstrates the portability of complex plastids between hosts.

The plastids of photosynthetic organisms on land are predominantly "primary plastids," derived from an ancient endosymbiosis of a cyanobacterium. Conversely, the plastids of marine photosynthetic organisms were mostly gained through subsequent endosymbioses of photosynthetic eukaryotes generating so-called "complex plastids." The plastids of the major eukaryotic lineages-cryptophytes, haptophytes, ochrophytes, dinoflagellates, and apicomplexans-were posited to derive from a single secondary endosymbiosis of a red alga in the "chromalveloate" hypothesis.

DynaMight: estimating molecular motions with improved reconstruction from cryo-EM images.

How to deal with continuously flexing molecules is one of the biggest outstanding challenges in single-particle analysis of proteins from cryogenic-electron microscopy (cryo-EM) images. Here, we present DynaMight, a software tool that estimates a continuous space of conformations in a cryo-EM dataset by learning three-dimensional deformations of a Gaussian pseudo-atomic model of a consensus structure for every particle image. Inversion of the learned deformations is then used to obtain an improved reconstruction of the consensus structure.

Structure of the native γ-tubulin ring complex capping spindle microtubules.

Microtubule (MT) filaments, composed of α/β-tubulin dimers, are fundamental to cellular architecture, function and organismal development. They are nucleated from MT organizing centers by the evolutionarily conserved γ-tubulin ring complex (γTuRC). However, the molecular mechanism of nucleation remains elusive.

Structural mechanism of outer kinetochore Dam1-Ndc80 complex assembly on microtubules.

Kinetochores couple chromosomes to the mitotic spindle to segregate the genome during cell division. An error correction mechanism drives the turnover of kinetochore-microtubule attachments until biorientation is achieved. The structural basis for how kinetochore-mediated chromosome segregation is accomplished and regulated remains an outstanding question.

Cryo-EM structure of the complete inner kinetochore of the budding yeast point centromere.

The point centromere of budding yeast specifies assembly of the large kinetochore complex to mediate chromatid segregation. Kinetochores comprise the centromere-associated inner kinetochore (CCAN) complex and the microtubule-binding outer kinetochore KNL1-MIS12-NDC80 (KMN) network. The budding yeast inner kinetochore also contains the DNA binding centromere-binding factor 1 (CBF1) and CBF3 complexes.