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J S Song

Publications and source records attributed to J S Song.

48 records · Page 3Linked to original sources
PubMed1995

Tau protein kinase I/GSK-3 beta/kinase FA in heparin phosphorylates tau on Ser199, Thr231, Ser235, Ser262, Ser369, and Ser400 sites phosphorylated in Alzheimer disease brain.

Previously, tau protein kinase I/glycogen synthase kinase-3 beta/kinase FA(TPKI/GSK-3 beta/FA) was identified as a brain microtubule-associated tau kinase possibly involved in the Alzheimer disease-like phosphorylation of tau. In this report, we find that the TPKI/GSK-3 beta/FA can be stimulated to phosphorylate brain tau up to 8.5 mol of phosphates per mol of protein by heparin, a polyanion compound. Tryptic digestion of 32P-labeled tau followed by high-performance liquid chromatography and high-voltage electrophoresis/thin-layer chromatography reveals 12 phosphopeptides. Phosphoamino acid analysis together with sequential manual Edman degradation and peptide sequence analysis further reveals that TPKI/GSK-3 beta/FA after heparin potentiation phosphorylates tau on sites of Ser199, Thr231, Ser235, Ser262, Ser396, and Ser400, which are potential sites abnormally phosphorylated in Alzheimer tau and potent sites responsible for reducing microtubule binding possibly involved in neuronal degeneration. The results provide initial evidence that TPKI/GSK-3 beta/FA after heparin potentiation may represent one of the most potent systems possibly involved in the abnormal phosphorylation of PHF-tau and neuronal degeneration in Alzheimer disease brains.

Alzheimer Disease↗
PubMed1993

Cyclic modulation of cross-linking interactions of microtubule-associated protein-2 with actin and microtubules by protein kinase FA.

The ATP.Mg-dependent type-1 protein phosphatase activating factor (factor FA) was identified as a brain protein kinase that could phosphorylate microtubule-associated protein-2 (MAP-2) and thereby inhibit cross-linking interactions of MAP-2 with actin filaments and microtubules isolated from porcine brain. The phosphorylation sites were found to be equally located on both projection and microtubule-binding domains of MAP-2. Phosphoamino acid analysis revealed that the phosphorylation sites were on both serine and threonine residues, indicating that factor FA is a serine/threonine-specific MAP-2 kinase. Conversely, factor FA was further identified as a MAP-2 phosphatase activator that could promote the dephosphorylation of 32P-MAP-2 phosphorylated by factor FA itself and thereby potentiate cross-linking interactions of MAP-2 with actin and microtubules. Furthermore, the two opposing functions of factor FA can be selectively modulated in a reciprocal manner by pH change. For instance, alkaline pH could stimulate factor FA to work as a MAP-2 kinase but simultaneously block it to work as a MAP-2 phosphatase activator to potentiate the inhibition on the cross-linking interactions of MAP-2 with actin and microtubules. Taken together, the results provide initial evidence that a cyclic modulation of cross-linking interactions of MAP-2 with actin filaments and microtubules can be controlled by factor FA, representing an efficient cyclic cascade control mechanism for rapid structural and functional regulation of neuronal cytoskeletal system.

Actins↗
PubMed1993

Protein kinase FA/GSK-3 phosphorylates tau on Ser235-Pro and Ser404-Pro that are abnormally phosphorylated in Alzheimer's disease brain.

Previously, we identified protein kinase FA/glycogen synthase kinase-3 (GSK-3) as a microtubule-associated protein tau kinase that can incorporate 4 mol of phosphates into 1 mol of tau protein and cause its electrophoretic mobility shift in sodium dodecyl sulfate gels, a unique property characteristic of paired helical filament-associated pathological tau (PHF-tau) in Alzheimer's disease brains. In this report, we identified TPPKS(p)PSAAK and SPVVSGDTS(p)PR as two phosphorylation site sequences phosphorylated by kinase FA/GSK-3 in tau using peptide sequence analysis and sequential manual Edman degradation for radiosequencing. When mapping with human brain tau sequence, we further identified Ser235-Pro and Ser404-Pro as the two major phosphorylation sites according to the numbering of the longest tau isoform. Ser235 and Ser404 have been reported as two of the major abnormal phosphorylation sites in PHF-tau. Taken together, the results provide initial evidence that protein kinase FA/GSK-3 may represent one of the Ser-Pro motif-directed tau kinases involved in the abnormal phosphorylation of pathological PHF-tau in Alzheimer's disease brain.

Alzheimer Disease↗
PubMed1992

Cyclic inhibition-potentiation of the crosslinking of synapsin I with brain microtubules by protein kinase FA (an activator of ATP.Mg-dependent protein phosphatase).

The ATP.Mg-dependent type-1 protein phosphatase activating factor (FA) was identified as a protein kinase that could phosphorylate synapsin I, a neuronal protein that coats synaptic vesicles, binds to cytoskeleton and is believed to be involved in the modulation of neurotransmission. More importantly, more than 90% of the phosphates in 32P-synapsin I phosphorylated by FA could be removed by the activated ATP.Mg-dependent type-1 protein phosphatase and the synapsin I phosphatase activity was found to be strictly FA-dependent. Functional study further revealed that as a synapsin I kinase, factor FA could phosphorylate synapsin I and thereby inhibits crosslinking of synapsin I with tubulin, while as a synapsin I phosphatase activator, FA could promote the crosslinking copolymerization of synapsin I with tubulin. Taken together, the results provide initial evidence that a cyclic modulation of the crosslinking copolymerization of synapsin I with brain microtubules can be controlled by factor FA, representing an efficient cyclic cascade control mechanism for the regulation of axonal transport process during neurotransmission.

Animals↗
PubMed1992

Identification of the ATP.Mg-dependent protein phosphatase activator (FA) as a synapsin I kinase that inhibits cross-linking of synapsin I with brain microtubules.

The ATP.Mg-dependent protein phosphatase activating factor (FA) has been identified and purified to near homogeneity from brain. In this report, as evidenced on SDS-polyacrylamide gel electrophoresis followed by autoradiography, factor FA has further been identified as a cAMP and Ca(2+)-independent brain kinase that could phosphorylate synapsin I, a neuronal protein that coats synaptic vesicles, binds to cytoskeleton, and is believed to be involved in the modulation of neurotransmission. Kinetic study further indicated that factor FA could phosphorylate synapsin I with a low Km value of about 2 microM and with a molar ratio of 1 mol of phosphate per mole of protein. Peptide mapping analysis revealed that factor FA specifically phosphorylated the tail region of synapsin I but on a unique site distinct from those phosphorylated by Ca2+/calmodulin-dependent protein kinase II and cAMP-dependent protein kinase, the two well-established synapsin I kinases. Functional study further revealed that factor FA could phosphorylate this unique specific site on the tail region of synapsin I and thereby inhibit cross-linking of synapsin I with microtubules. The results further suggest the possible involvement of factor FA as a synapsin I kinase in the regulation of axonal transport process of synaptic vesicles via the promotion of vesicles motility during neurotransmission.

Adenosine Triphosphate↗
PubMed1991

Selective modulation of the two antagonistic activities of protein kinase FA (the activator of ATP.Mg-dependent protein phosphatase).

The ATP.Mg-dependent protein phosphatase activating factor (FA) has been identified as a protein kinase. The results are unexpected since factor FA possesses two activities which are antagonistic. As a kinase, factor FA catalyzes protein phosphorylation, while as a phosphatase activator, it catalyzes protein dephosphorylation. In this report, we found that the two opposing activities of factor FA could be selectively modulated. For instance, heparin at concentrations of 0.1-0.3 mg/ml could stimulate FA to work preferentially as a kinase towards phosphorylation of proteins but simultaneously inhibit it to work as a phosphatase activator towards dephosphorylation of the same proteins. In a similar manner, alkaline pH could stimulate FA to work as a kinase but block it to work as a phosphatase activator. This is the first report providing initial evidence that the two opposing activities of factor FA can be selectively modulated in a reciprocal manner by various triggers, suggesting that a simultaneous coordinate control mechanism may well be involved in regulating the activities of factor FA in the cell.

Adenosine Triphosphate↗
PubMed1989

Epidermal growth factor induces activation of protein kinase FA and ATP.Mg-dependent protein phosphatase in A431 cells.

The cytosolic fractions from epidermal growth factor (EGF)-treated A431 cells exhibit a marked increase in activities of ATP.Mg-dependent protein phosphatase and its activating factor (protein kinase FA) when compared to controls in the absence of EGF. By contrast, the Triton X-100-solubilized membrane fractions from the same EGF-treated cells exhibit a corresponding decrease in protein kinase FA activity. The EGF-dependent activation of protein kinase FA and ATP.Mg-dependent protein phosphatase occurred within physiological concentrations of EGF (ED50 = 5 x 10(-10) M). The changes of kinase and phosphatase activities which were measured concomitantly exhibit very similar characteristics as to EGF sensitivity and time dependence. The EGF-induced kinase and phosphatase activation occurred very rapidly, reaching the maximal activity levels within 3 min. Moreover, the EGF effect is transient; both EGF-stimulated phosphatase and kinase activities returned to control levels within 30 min. Taken together, the results suggest that EGF may induce the activation of kinase FA in the membrane and thereby promotes the activation of ATP.Mg-dependent phosphatase in the cytosol. Exposure of A431 cells to exogenous phospholipase C also resulted in the activation of endogenous kinase FA and ATP.Mg-dependent phosphatase in a similar pattern produced by EGF. This further suggests that phospholipase C can mimic EGF to mediate the activation of kinase FA and ATP.Mg-dependent phosphatase in A431 cells. By its dual role as a multisubstrate protein kinase and as an activating factor of multisubstrate protein phosphatase, protein kinase FA may represent a transmembrane signal of EGF.

Adenosine Triphosphate↗
PubMedDate not supplied

Effect of temperature on the breakthrough of a charcoal tube during vinyl chloride monomer sampling.

This study evaluated the effects of temperature on breakthrough of two standard collection media at various concentrations during vinyl chloride monomer (VCM) sampling. The National Institute for Occupational Safety and Health (NIOSH) and Occupational Safety and Health Administration (OSHA) methods were evaluated. To determine whether breakthrough of VCM would occur at the extremes of exposure and temperature that might be encountered in some workplaces, air samples containing 4 ppm (10.24 mg/m3), 8 ppm (20.45 mg/m3), 16 ppm (40.98 mg/m3), and 32 ppm (81.80 mg/m3) of VCM were collected at temperatures of 4, 22, and 40 degrees C. Five liters of air was sampled at the rate of 0.05 L/min for 100 min using the activated charcoal tube recommended by NIOSH. A second tube was added to the sampling train to collect any VCM that might not have been absorbed in the first tube. To collect VCM air samples by the OSHA method, two carbon molecular sieve tubes were connected serially and 3 L of air was sampled at the rate of 0.05 L/min for 60 min. A gas chromatograph with a flame ionization detector and ultra 2 capillary column was used to analyze VCM. Significant breakthrough was found when sampling at higher temperatures with the NIOSH method. No breakthrough was found when samples were collected using the OSHA media at different temperatures and concentrations. Therefore, under hot ambient conditions (>22 degrees C), the possibility of breakthrough should be considered when sampling VCM by the NIOSH method.

Air Pollutants, Occupational↗
PubMedDate not supplied

Possibility of reciprocal infection of methicillin-resistant Staphylococcus aureus between medical personnel and patients undergoing middle ear surgery.

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection after middle ear surgery has recently increased in our hospital. In this study we tried to determine whether the strains of MRSA isolated from infected patients are identical to those obtained from medical personnel, to prove a reciprocal transmission between medical personnel and patients. Surveillance bacterial cultures of medical personnel were performed from the anterior nares and from the fingertip. Molecular epidemiological studies, ribotyping and pulsed-field gel electrophoresis (PFGE) were used to compare the 12 MRSA strains obtained from carriers among medical personnel with the 60 strains identified from patient's otorrhea. Six different MRSA strains were identified from ribotyping, and three subtypes from PFGE. There was a particular subtype which was the most frequently identified strain found in both medical carriers and patients. Postoperative MRSA infection rates after the treatment of medical carriers and application of preventive procedures decreased from 11.9 to 5.7%. These findings suggest that the MRSA transmissions have occurred between medical personnel and patients.

Cross Infection↗