What is the cellular origin of hematopoietic stem cells? Based on findings from a large number of anatomical, biochemical, and genetic studies carried out over the years, three major theories have been put forth to describe the cellular origin of hematopoietic stem cells. Although [...]

How are lipids and protein complexes segregated during cell polarization? In polarized epithelial cells, the apical membrane is rich in PIP2 and houses the PAR and Crumbs polarity complexes while the basal membrane contains PIP3 and the Scribble polarity complex [1][2]. The phosphatase PTEN, [...]

How is the cytoskeleton polarized? As well as the asymmetric organization of cellular components, polarity can also be defined through the structural orientation of the cytoskeleton, in particular, actin filaments and microtubules. This is important in cell migration and motility, which requires a front-rear [...]

What is the epithelial to mesenchymal transition? Epithelial to mesenchymal transition (EMT) is the process whereby epithelial cells are transformed into mesenchymal cells. Epithelial cells form the epithelium tissue which covers the internal and external body surface of an organism. These cells are polarized [...]

What is the mesenchymal-epithelial transition? During development, the transitioning of epithelial cells to a mesenchymal lineage is not an irreversible process. Instead, a number of developmental programs are accompanied by a reversal of EMT, during which the mesenchyme gets dedifferentiated into the epithelial lineage [...]

What is hematopoiesis? The hematopoietic system, which comprises all the cellular components of the blood, is one of the earliest organ systems to evolve during embryo development. Hematopoietic stem cells (HSCs), which are rare blood cells residing in the bone marrow of the adult [...]