Marine dinoflagellates of the genus Alexandrium are the proximal source of neurotoxins associated with Paralytic Shellfish Poisoning. The production of these toxins, the toxin biosynthesis and, thus, the cellular toxicity can be influenced by abiotic and biotic factors. There is, however, a lack of substantial evidence concerning the toxins' ecological function such as grazing defense. Waterbor...

The serine/threonine kinase p21-activated kinase 1 (Pak1) modulates actin and microtubule dynamics. The neuronal functions of Pak1, despite its abundant expression in the brain, have not yet been fully delineated. Previously, we reported that Pak1 mediates initiation of dendrite formation. In the present study, the role of Pak1 in dendritogenesis, spine formation and maintenance was examined in...

We examined the metal ion cofactor preference for MST3 (mammalian Ste20-like kinase 3) of the Ste20 serine/threonine kinase family. Four metal ions (Mg(+2), Mn(+2), Zn(2+), and Co(2+)) activate endogenous, exogenous, and baculovirus-expressed recombinant MST3 within the physiological concentration range. In contrast, Fe(+2) and Ca(+2) do not function as MST3 cofactors. Mn(2+), Co(2+), and Mg(2+...

The role of Transforming Growth Factor beta (TGF-beta)-related molecules in axis formation and mesoderm patterning in vertebrates has been extensively documented, but the identity and mechanisms of action of the endogenous molecules remained uncertain. In this study, we isolate a novel serine/threonine kinase type I receptor, TARAM-A, expressed during early zebrafish embryogenesis first ubiquit...

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 cytoskelet...

Since the isolation of cyclin-dependent kinase 5 (Cdk5), this proline-directed serine/threonine kinase has been demonstrated as an important regulator of neuronal migration, neuronal survival and synaptic functions. Recently, a number of players implicated in dendrite and synapse development have been identified as Cdk5 substrates. Neurite extension, synapse and spine maturation are all modulat...

Checkpoint kinase 2 (CHEK2) is a serine/threonine kinase which is activated upon DNA damage and is implicated in pathways that govern DNA repair, cell cycle arrest or apoptosis in response to the initial damage. Loss of kinase function has been correlated with different types of cancer, mainly breast cancer. CHEK2 functionality is affected by different missense or deleterious mutations. CHEK2*1...

Temporal control of neuronal differentiation is critical to produce a complete and fully functional nervous system. Loss of the precise temporal control of neuronal cell fate can lead to defects in cognitive development and to disorders such as epilepsy and autism. Mechanistic target of rapamycin (mTOR) is a large serine/threonine kinase that acts as a crucial sensor of cellular homeostasis. mT...

The finding that insulin-like growth factor (IGF)-binding protein-5 (IGFBP-5) binding to mouse osteoblasts was capable of being downregulated by IGFBP-5 suggested that the 420-kDa membrane protein, which interacted with IGFBP-5, may be a signaling receptor (Andress, D. L. J. Biol. Chem. 270: 28289-28296, 1995). In the current study, a carboxy-terminal IGFBP-5 peptide, IGFBP-5-(201-218), which w...

To investigate the catalytic properties of the Brassica oleracea S-locus receptor kinase (SRK), we have expressed the domain that is homologous to protein kinases as a fusion protein in Escherichia coli. Following in vivo labeling of cultures with 32P-labeled inorganic phosphate, we observed phosphorylation of the fusion protein on serine and threonine, but not on tyrosine. In contrast, labelin...