EspM inhibits pedestal formation by enterohaemorrhagic Escherichia coli and enteropathogenic E. coli and disrupts the architecture of a polarized epithelial monolayer.

Enterohaemorrhagic Escherichia coli and enteropathogenic E. coli are enteropathogens characterized by their ability to induce the host cell to form actin-rich structures, termed pedestals. A type III secretion system, through which the pathogens deliver effector proteins into infected host cells, is essential for their virulence and pedestal formation.

Transcriptional activation of a subset of hair keratin genes by the NF-kappaB effector p65/RelA.

The hair follicle is an intricate miniature organ dedicated to the production of the structural hair fiber, which is largely composed of hair keratin (HK) proteins. Many developmental pathways contribute to hair follicle development; however, the molecular control of HK genes is still far from being resolved. Because the nuclear factor (NF)-kappaB pathway is known to be involved in the morphogenesis of the hair follicle, we explored the possibility that it may also regulate HK expression.

Cholesterol-sensitive modulation of transcytosis.

Cholesterol-rich membrane domains (e.g., lipid rafts) are thought to act as molecular sorting machines, capable of coordinating the organization of signal transduction pathways within limited regions of the plasma membrane and organelles.

Dynamic expression of Runx1 in skin affects hair structure.

The three mammalian Runx transcription factors, some of which are known to be involved in human genetic diseases and cancer, are pivotal players in embryo development and function as key regulators of cell fate determination and organogenesis. Here, we report the expression of Runx1 during the development of hair and other skin appendages in the mouse and describe the effect of Runx1 on the structural hair output. In hair follicles, where the three Runx proteins are expressed, Runx1 expression is most prominent in both mesenchymal and epithelial compartments.

An essential role for the C-terminal domain of a dragline spider silk protein in directing fiber formation.

We have employed baculovirus-mediated expression of the recombinant A. diadematus spider dragline silk fibroin rADF-4 to explore the role of the evolutionary conserved C-terminal domain in self-assembly of the protein into fiber. In this unique system, polymerization of monomers occurs in the cytoplasm of living cells, giving rise to superfibers, which resemble some properties of the native dragline fibers that are synthesized by the spider using mechanical spinning.

Runx3 is involved in hair shape determination.

Transcriptional regulators of the Runx family play critical roles in normal organ development and, when mutated, lead to genetic diseases and cancer. Runx3 functions during cell lineage decisions in thymopoiesis and neurogenesis and mediates transforming growth factor-beta signaling in dendritic cells. Here, we study the function of Runx3 in the skin and its appendages, primarily the hair follicle, during mouse development.

Novel assembly properties of recombinant spider dragline silk proteins.

Spider dragline silk, which exhibits extraordinary strength and toughness, is primarily composed of two related proteins that largely consist of repetitive sequences. In most spiders, the repetitive region of one of these proteins is rich in prolines, which are not present in the repetitive region of the other. The absence of prolines in one component was previously speculated to be essential for the thread structure.