Mitotic Acetylation of Microtubules Promotes Centrosomal Recruitment and Is Required to Maintain Bipolar Spindle Homeostasis.

Tubulin post-translational modifications regulate microtubule properties and functions. Mitotic spindle microtubules are highly modified. While tubulin detyrosination promotes proper mitotic progression by recruiting specific microtubule-associated proteins motors, tubulin acetylation that occurs on specific microtubule subsets during mitosis is less well understood.

PAK1 Regulates MEC-17 Acetyltransferase Activity and Microtubule Acetylation during Proplatelet Extension.

Mature megakaryocytes extend long processes called proplatelets from which platelets are released in the blood stream. The Rho GTPases Cdc42 and Rac as well as their downstream target, p21-activated kinase 2 (PAK2), have been demonstrated to be important for platelet formation. Here we address the role, during platelet formation, of PAK1, another target of the Rho GTPases.

Microtubule polyglutamylation and acetylation drive microtubule dynamics critical for platelet formation.

Background: Upon maturation in the bone marrow, polyploid megakaryocytes elongate very long and thin cytoplasmic branches called proplatelets. Proplatelets enter the sinusoids blood vessels in which platelets are ultimately released. Microtubule dynamics, bundling, sliding, and coiling, drive these dramatic morphological changes whose regulation remains poorly understood.

Early gametogenesis in the Pacific oyster: new insights using stem cell and mitotic markers.

While our knowledge of bivalve gametogenesis has progressed in recent times, more molecular markers are needed in order to develop tissue imaging. Here, we identified stem cell and mitotic markers to further characterize oyster early gametogenesis, mainly through immunofluorescence microscopy. Intense alkaline phosphatase activity, a non-specific marker for stem cells, was detected on the outer edge of the gonad ducts at the post-spawning stage, suggesting an abundance of undifferentiated cells very early during the sexual cycle.

Adult somatic progenitor cells and hematopoiesis in oysters.

Long-lived animals show a non-observable age-related decline in immune defense, which is provided by blood cells that derive from self-renewing stem cells. The oldest living animals are bivalves. Yet, the origin of hemocytes, the cells involved in innate immunity, is unknown in bivalves and current knowledge about mollusk adult somatic stem cells is scarce.