CD44 is implicated in cell-cell and cell-matrix adhesion, cell migration, and signaling. CD44 cleavage correlates with the tumor burden and metastatic potential in various cancers. In this study, we demonstrate that matrix metalloproteinase-9 (MMP-9) acts as a processing enzyme for CD44 cleavage. Further, this processing event stimulates cell motility and inhibition of either CD44 or MMP-9 inhi...

This research shows that myoplasmic crescent material of the ascidian egg has both functional autonomy and functional specificity in establishing the differentiation pathway of muscle lineage cells. The cytoplasmic segregation pattern in eggs of Styela plicata was altered by compression of the embryos during third cleavage. This caused a meridional division instead of the normal equatorial thir...

Most of the small ribozymes, including those that have been investigated as potential therapeutic agents, appear to be rather poor catalysts. These RNAs use an internal phosphoester transfer mechanism to catalyze site-specific RNA cleavage with apparent cleavage rate constants typically <2 min(-1). We have identified variants of one of these, the Neurospora Varkud satellite ribozyme, that self-...

The laminin-binding integrin a6b1 plays a major role in determining the aggressive phenotype of tumor cells during metastasis. Our previous work has shown that cleavage of the a6b1 integrin to produce the structural variant a6pb1 on tumor cell surfaces is mediated by the serine protease urokinase plasminogen activator (uPA). Cleavage of a6b1 increases tumor cell motility, invasion, and prostate...

Accumulation of putrescine in ornithine decarboxylase overproducing cells provokes apoptotic death that is inhibited by 2-difluoromethylornithine, a specific inhibitor of ODC. The apoptotic process provoked by putrescine involves the release of cytochrome c from the mitochondria and activation of caspases cascades demonstrated by the cleavage of caspase-2, polyA-ribose polymerase (PARP), and pr...

During early cleavages of Sicyonia ingentis embryos, mitotic spindle orientations differ between blastomeres and change in a predictable manner with each successive mitosis. From 2nd through 7th cleavages, spindles orient at a 90 degrees angle with respect to the spindle of the parent blastomere. Thus, spindle orientation is parallel to the cleavage plane that formed the blastomere. To determin...

Cleavage of poly(ADP-ribose) polymerase (PARP) by caspases is a prominent characteristic of apoptosis or programmed cell death shown to be induced by topoisomerase (Topo) inhibitors. Because Topo I inhibitors have been shown to be effective in the treatment of some patients with colon cancer, we considered the possibility of using PARP cleavage as an early predictor of responsiveness to this cl...

Amphiregulin, like other ErbB ligands, is synthesized as a pro-protein which requires cleavage at the cell surface to release the active signaling domain. Prior studies using a variety of approaches have not yielded a consensus about the precise cleavage site. Here we report the purification and protein sequencing of the cell-associated human Amphiregulin stalk which remains following cleavage ...

To complete the cell cycle, the cleavage furrow draws the plasma membrane toward the cell center, pinching the cytoplasm into two lobes that are subsequently separated into two cells. The position of the cleavage furrow is induced by the mitotic spindle during early anaphase. Although the mechanism of cleavage furrow positioning is not understood at a molecular level, recent results suggest tha...

Introduction: Women with poorly controlled insulin-dependent diabetes mellitus (IDDM) have a much higher incidence of early pregnancy complications, these include spontaneous miscarriages, early growth delay, and congenital malformations. Most of the investigations have been devoted to the early post implantation and organogenesis period of pregnancy. In this research we studied the hyperglycem...