Background—Many cells that migrate during normal embryonic development or in metastatic cancer first detach from an epithelium. However, this step is often difficult to observe directly in vivo and the mechanisms controlling the ability of cells to leave the epithelium are poorly understood. In addition, once cells detach, they must assume a migratory phenotype, involving changes in cytoskeleta...

The serine/threonine kinase, PAR-1, is an essential component of the evolutionary-conserved polarity-regulating system, PAR-aPKC system, which plays indispensable roles in establishing asymmetric protein distributions and cell polarity in various biological contexts (Suzuki, A. and Ohno, S. (2006). J. Cell Sci., 119: 979-987; Matenia, D. and Mandelkow, E.M. (2009). Trends Biochem. Sci., 34: 332...

Kinases are key targets for drug discovery. In the field of screening in general and especially in the kinase area, because of considerations of efficiency and cost, radioactivity-based assays tend to be replaced by alternative, mostly fluorescence-based, assays. Today, the limiting factor is rarely the number of data points that can be obtained but rather the quality of the data, enzyme availa...

Seven DNA fragments containing putative protein serine/threonine kinase genes were cloned from Streptomyces coelicolor A3(2) by hybridization with a 165-bp amplified polymerase chain reaction product of pkaB containing kinase subdomains VI, VII and VIII. Among them, the nucleotide sequences of three fragments containing subdomains VI, VII and VIII were identical, while those of one fragment wer...

3'-phosphoinositide-dependent protein kinase-1 (PDK-1) is a crucial serine/threonine kinase in the insulin-like growth factor-I (IGF-I)/AKT signaling pathway, but its function and localization in the nervous system has not been fully characterized. In this study, we compared the localization of PDK-1 in adult neurons and non-neuronal PC-3 cells. We showed that PC-3 cells expressed phosphorylate...

During the development of the nervous system, apicobasally polarized stem cells are characterized by a shorter cell cycle than nonpolar progenitors, leading to a lower differentiation potential of these cells. However, how polarization might be directly linked to the kinetics of the cell cycle is not understood. Here, we report that apicobasally polarized neuroepithelial cells in Xenopus laevis...

Recent studies have consolidated the pivotal role of Smads as intracellular effectors of TGF-beta family members. Upon binding to their specific type I and type II serine/threonine kinase receptors, each family member activates a particular subset of Smad proteins. Activated, receptor-regulated Smads form hetero-oligomeric complexes with common-partner Smads that translocate into the nucleus, w...

Prk1p is a serine/threonine kinase involved in the regulation of the actin cytoskeleton organization in the yeast Saccharomyces cerevisiae. Previously, we have identified LxxQxTG as the phosphorylation site of Prk1p. In this report, the recognition sequence for Prk1p is investigated more thoroughly. It is found that the presence of a hydrophobic residue at the position of P-5 is necessary for P...

We have identified a serine/threonine kinase that is rapidly activated during Fas-mediated apoptosis. Fas-activated serine/threonine kinase (FAST) is phosphorylated on serine and threonine residues in Jurkat cells. In response to Fas ligation, it is rapidly dephosphorylated and concomitantly activated to phosphorylate TIA-1, a nuclear RNA-binding protein that has been implicated as an effector ...

FoxO transcription factors control development and longevity in diverse species. Although FoxO regulation via changes in its subcellular localization is well established, little is known about how FoxO activity is regulated in the nucleus. Here, we show that the conserved C. elegans protein EAK-7 acts in parallel to the serine/threonine kinase AKT-1 to inhibit the FoxO transcription factor DAF-...