Microtubule severing by elongation factor 1 alpha.

An activity that severs stable microtubules is thought to be involved in microtubule reorganization during the cell cycle. Here, a 48-kilodalton microtubule-severing protein was purified from Xenopus eggs and identified as translational elongation factor 1 alpha (EF-1 alpha). Bacterially expressed human EF-1 alpha also displayed microtubule-severing activity in vitro and, when microinjected into fibroblasts, induced rapid and transient fragmentation of cytoplasmic microtubule arrays.

In vivo induction of IgG anti-DNA antibody by autoreactive mixed haplotype A beta z/A alpha d MHC class II molecule-specific CD4+ T-cell clones.

We characterized autoreactive T-cell clones derived from (NZB x NZW)F1 (B/WF1) mice. These autoreactive T-cell clones are shown to be CD4+ by immunofluorescence staining and to belong to Th2 type by cytokine release assay. Specificity analysis revealed the existence of mixed haplotype A beta z/A alpha d major histocompatibility complex (MHC) class II molecule-specific T-cell clones as well as A beta z/A alpha z- or A beta d/A alpha d-specific T-cell clones.

Increased Fas antigen expression in murine retrovirus-induced immunodeficiency syndrome, MAIDS.

The Fas antigen (Fas), which is a cell surface protein belonging to the tumor necrosis factor receptor family, mediates apoptosis. To assess the contribution of Fas to the pathogenesis of retrovirus-induced immunodeficiency, we examined the kinetics of Fas expression on the lymphocytes during the course of murine acquired immunodeficiency syndrome (MAIDS) induced by a defective LP-BM5 murine leukemia virus. The Fas-positive cells were increased in proportion both in alpha beta T cells and B cells with the progression of MAIDS.

Stimulatory effects of yeast and mammalian 14-3-3 proteins on the Raf protein kinase.

Intracellular signaling from receptor tyrosine kinases in mammalian cells results in activation of a signal cascade that includes the guanine nucleotide-binding protein Ras and the protein kinases Raf, MEK [mitogen-activated protein kinase (MAPK) or extracellular signal-regulated kinase (ERK) kinase], and MAPK. MAPK activation that is dependent on the coupling of Ras and Raf was reconstituted in yeast. Yeast genes were isolated that, when overexpressed, enhanced the function of Raf.

Selective extractability of noncollagenous proteins from chicken bone.

Quantitative analyses of a wide variety of different solvents used for the extraction of several of the noncollagenous proteins of fully mineralized chicken bone powder were carried out to compare both the effectiveness of various procedures and the distribution of specific proteins which were solubilized. Extraction procedures included solutions of 6 M guanidine-HCl, pH 7.0, 0.

[Depressive symptoms of the care-takers of non-institutionalised bedridden cerebrovascular patients].

Forty care-takers providing in-home care of elderly CVD patients were assessed with Zung's depression test and the following results were obtained. 1. Most of the care-takers were female with a mean age of 56 years (41 to 81 years).

Characterization of recombinant Xenopus MAP kinase kinases mutated at potential phosphorylation sites.

Xenopus mitogen-activated protein kinase kinase (MAPKK) previously inactivated with protein phosphatase 2A can be reactivated by serine phosphorylation catalyzed by a partially purified MAPKK kinase (MAPKK-K), and is phosphorylated by MAPK on a threonine residue. The sequence analysis of a threonine-phosphorylated tryptic peptide of Xenopus MAPKK from mature oocytes suggested that Thr388 is phosphorylated in vivo. A mutant MAPKK that has Thr388 changed to Ala (T388A-MAPKK) was not phosphorylated by purified MAPK, indicating that Thr388 is phosphorylated by MAPK.

Feedback regulation of mitogen-activated protein kinase kinase kinase activity of c-Raf-1 by insulin and phorbol ester stimulation.

Recently, it has been reported that Raf-1 kinase (Raf-1) has mitogen-activated protein kinase kinase kinase (MAPKKK) activity in various cells, although Raf-1 and MAP kinase kinase (MAPKK) can be phosphorylated by MAP kinase (MAPK) in vitro. Here we show that the maximal hyperphosphorylation of Raf-1 and MAPKK (10 min) was substantially achieved after the maximal activation of MAPKKK of Raf-1, MAPKK (2-5 min), and MAPK in Chinese hamster ovary cells overexpressing human insulin receptor (CHO-HIR cells) treated with insulin or 12-O-tetradecanoylphorbol-13-acetate (TPA). Moreover, we show that overexpression of MAPK in CHO-HIR cells resulted in enhanced hyperphosphorylation of Raf-1, MAPKK, and mammalian homolog of son of sevenless (mSos) after insulin or TPA stimulation as compared with parental cells.

Requirement for the MAP kinase kinase/MAP kinase cascade in Xenopus oocyte maturation.

MAP kinase kinase (MAPKK) has been identified as a protein factor that can induce phosphorylation and activation of inactive MAP kinase in vitro. In this study, we produced an anti-Xenopus MAPKK antibody that can specifically inhibit Xenopus MAPKK activity in vitro. Microinjection of this antibody into immature oocytes prevented progesterone-induced MAP kinase activation.

Functional coupling of SSTR4, a major hippocampal somatostatin receptor, to adenylate cyclase inhibition, arachidonate release and activation of the mitogen-activated protein kinase cascade.

Somatostatin has a modulatory role in regulating the membrane conductance in hippocampal neurons. To examine the signal transducing molecules involved in this process, we isolated the cDNA encoding the dominant rat hippocampal somatostatin receptor, SSTR4. Distribution of SSTR4 in the adult central nervous system was restricted to the hippocampus, cerebral cortex, striatum, hypothalamus, and thalamus, as determined by Northern blot analysis and in situ hybridization.

Long-term effects of bone marrow transplantation for inborn errors of metabolism: a study of four patients with lysosomal storage diseases.

Long-term effects of bone marrow transplantation (BMT) were evaluated in patients with I-cell disease, metachromatic leukodystrophy (MLD), Maroteaux-Lamy syndrome or Hunter syndrome (mild form). Donors were human leukocyte antigen (HLA)-matched siblings, and the follow-up periods were 24-71 months after BMT. The enzyme activities were increased in leukocytes, plasma or liver tissues compared with pre-BMT levels.

Crystal Structure of the High-Pressure Phase of Solid CO2.

X-ray diffraction study of solid CO(2) at room temperature has shown that the powder pattern of the high-pressure phase, which supersedes the low-pressure cubic Pa3 phase at about 10 gigapascals, is consistently interpreted in terms of an orthorhombic Cmca structure. The orthorhombic cell at 11.8 gigapascals has dimensions of 4.

Transfected platelet-activating factor receptor activates mitogen-activated protein (MAP) kinase and MAP kinase kinase in Chinese hamster ovary cells.

The platelet-activating factor (PAF) was seen to potently activate mitogen-activated protein (MAP) kinase and MAP kinase kinase through the cloned guinea pig PAF receptor stably expressed in Chinese hamster ovary (CHO) cells. Both 42- and 44-kDa MAP kinases were activated and tyrosine-phosphorylated in response to PAF. The PAF receptor also triggered the production of inositol phosphates and the release of arachidonic acid and inhibited cyclic AMP accumulation.

Characterization of two cDNAs that encode MAP kinase homologues in Arabidopsis thaliana and analysis of the possible role of auxin in activating such kinase activities in cultured cells.

Two cDNA clones, cATMPK1 and cATMPK2, encoding MAP kinases (mitogen-activated protein kinases) have been cloned from Arabidopsis thaliana and their nucleotide sequences have been determined. Putative proteins encoded by ATMPK1 and ATMPK2 genes, designated ATMPK1 and ATMPK2, contain 370 and 376 amino acid residues, respectively, and are 88.7% identical at the amino acid sequence level.

Immunological approach to Ménière's disease: vestibular immune injury following immune reaction of the endolymphatic sac.

Following direct antigen challenge to the endolymphatic sac (sac), the relation of caloric test results and spontaneous nystagmus to the histological changes of the sensory epithelium of the vestibular organ and perilymph antibody levels was investigated in the guinea pig. In a secondary keyhole limpet hemocyanin (KLH) challenge to the sac, irritative nystagmus was followed by paralytic nystagmus and a suppression of caloric reaction. These findings correlated well with the degree of degeneration of the sensory epithelium of the vestibular organ and the levels of perilymph antibody.

Regulation and function of the MAP kinase cascade in Xenopus oocytes.

In Xenopus oocytes, activation of MAP kinase occurs during meiotic maturation through a protein kinase cascade (the MAP kinase cascade), which is utilized commonly in various intracellular signaling pathways in eukaryotes. Studies with a neutralizing antibody against Xenopus MAP kinase kinase (MAPKK), a direct upstream activator for MAP kinase, have shown that the MAP kinase cascade plays a crucial role in both initiating oocyte maturation and inducing metaphase arrest.

[Surgical treatment of cardiac myxomas].

Between April 1975 to March 1991, 17 patients (5 man and 12 women, mean age 49.8 years old) underwent surgical treatment for cardiac myxomas. Fifteen patients had left atrial myxomas, and the other 2 had the ventricular myxomas (left ventricular myxoma 1 and right ventricular myxoma 1).

Chemical modification of silk fibroin with cyanuric chloride-activated poly(ethylene glycol): analyses of reaction site by 1H-NMR spectroscopy and conformation of the conjugates.

Solubilized silk fibroin (SF) in 0.1 M borate buffer (pH 9.4) was modified with 2-O-[methoxy(polyethylene glycol)]-4,6-dichloro-s-triazine (actPEG1) at 4 degrees C.

Schizosaccharomyces pombe Spk1 is a tyrosine-phosphorylated protein functionally related to Xenopus mitogen-activated protein kinase.

Mitogen-activated protein kinase (MAPK) and its direct activator, MAPK kinase (MAPKK), have been suggested to play a pivotal role in a variety of signal transduction pathways in higher eukaryotes. The fission yeast Schizosaccharomyces pombe carries a gene, named spk1, whose product is structurally related to vertebrate MAPK. Here we show that Spk1 is functionally related to Xenopus MAPK.

Mixed haplotype A beta Z/A alpha d class II molecule in (NZB x NZW)F1 mice detected by T cell clones.

We have tried to demonstrate the existence of a mixed haplotype MHC class II molecule in (NZB x NZW)F1 (B/WF1) mice. When a large panel of keyhole limpet hemocyanin-specific T cell clones derived from B/WF1 mice was analyzed, several clones were shown to be restricted by a F1-specific A beta Z/A alpha d class II molecule. Autoreactive A beta Z/A alpha d-specific T cell clones were also obtained.

A yeast mitogen-activated protein kinase homolog (Mpk1p) mediates signalling by protein kinase C.

Mitogen-activated protein (MAP) kinases are activated in response to a variety of stimuli through a protein kinase cascade that results in their phosphorylation on tyrosine and threonine residues. The molecular nature of this cascade is just beginning to emerge. Here we report the isolation of a Saccharomyces cerevisiae gene encoding a functional analog of mammalian MAP kinases, designated MPK1 (for MAP kinase).

The MAP kinase cascade is essential for diverse signal transduction pathways.

Mitogen-activated protein (MAP) kinases are activated by combined tyrosine and threonine phosphorylation catalysed by MAP kinase kinase, a novel class of protein kinases with dual specificity for both tyrosine and serine/threonine. MAP kinase kinase is turned on by serine/threonine phosphorylation catalysed by an immediate upstream kinase. The MAP kinase cascade appears to be conserved during evolution and thus might play an essential role in diverse intracellular signaling processes from yeasts to vertebrates.

Phosphorylation of Xenopus mitogen-activated protein (MAP) kinase kinase by MAP kinase kinase kinase and MAP kinase.

Xenopus 45-kDa mitogen-activated protein (MAP) kinase kinase (MAPKK) is a serine/threonine/tyrosine kinase, which activates MAP kinase (MAPK) by phosphorylating its threonine and tyrosine residues. MAPKK is active only when its threonine and/or serine residues are phosphorylated. We have identified from Xenopus eggs two protein kinases responsible for phosphorylation of MAPKK.