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41.
Identification of tyrosines 154 and 307 in the extracellular domain and 653 and 766 in the intracellular domain as phosphorylation sites in the heparin-binding fibroblast growth factor receptor tyrosine kinase (flg). 总被引:3,自引:0,他引:3
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J. Hou K. McKeehan M. Kan S. A. Carr M. J. Huddleston J. W. Crabb W. L. McKeehan 《Protein science : a publication of the Protein Society》1993,2(1):86-92
Four tyrosine residues have been identified as phosphorylation sites in the tyrosine kinase isoform of the heparin-binding fibroblast growth factor receptor flg (FGF-R1). Baculoviral-insect cell-derived recombinant FGF-R1 was phosphorylated and fragmented with trypsin while immobilized on heparin-agarose beads. Phosphotyrosine peptides were purified by chromatography on immobilized anti-phosphotyrosine antibody and analyzed by Edman degradation and electrospray tandem mass spectrometry. Tyrosine residue 653, which is in a homologous spatial position to major autophosphorylation sites in the catalytic domain of the src and insulin receptor kinases, is the major intracellular FGF-R1 phosphorylation site. Residue 766 in the COOH-terminus outside the kinase domain is a secondary site. Tyrosine residues 154 and 307, which are in the extracellular domain of transmembrane receptor isoforms and are in an unusual sequence context for tyrosine phosphorylation, were also phosphorylated. 相似文献
42.
Sergei Kan 《American anthropologist》2003,105(3):648-649
Against Culture: Development, Politics, and Religion in Indian Alaska. Kirk Dombrowski. Lincoln: University of Nebraska Press, 2001. 247 pp. 相似文献
43.
Koichi Matsuzaki Mikio Kan Wallace L. McKeehan 《In vitro cellular & developmental biology. Animal》1996,32(6):345-360
Summary Two transmembrane serine-threonine kinases (type I and II receptors), a membrane-anchored proteoglycan (type III), and a homodimeric
ligand participate in the transforming growth factor beta type on (TGFβ1) signal transduction complex. The expression of recombinant
receptors in insect cells co-infected with up to three recombinant baculoviruses was employed to study interactions among
the ectodomains of the three types of receptors and the TGFβ1 ligand in absence of uncontrollable extrinsic factors in mammalian
cells. Multi-subunit complexes were assembled in intact cells and purified on glutathione-conjugated beads for analysis by
tagging one of the subunits with glutathione S-transferase (GST). Intrinsic ligand-independent interactions were observed
among receptor subunits as follows: type III–III type I–I, type III-I, and type II-I. The homeotypic complex of type II–II
receptors and the heterotypic type III-II interaction was ligand dependent. The type I, but not the type III, subunit displaced
about 50% of the type II component in either ligand-dependent homomeric type II-type II complexes or heteromeric type III-type
II complexes to form type II-I or type III-II-I oligomers, respectively. The type II subunit displaced type I subunits in
oligomers of the type I subunit. Specificity of type I receptors may result from differential affinity for the type II receptor
rather than specificity for ligand. A monomeric subunit of the TGFβ1 ligand bound concurrently to type III and type II or
type III and type I receptors, but failed to concurrently bind to the type II and type I subunits. The binding of TGFβ1 to
the type I kinase subunit appears to require an intact disulfide-linked ligand dimer in the absence of a type III subunit.
The combined results suggest a pentameric TGFβ signal transduction complex in which one unit each of the type III, type II,
and type I components is assembled around the two subunits of the dimeric TGFβ1 ligand. An immobilized GST-tagged subunit
of the receptor complex was utilized to assemble multi-subunit complexesin vitro and to study the phosphorylation events among subunits in the absence of extrinsic cell-derived kinases. The results revealed
that (a) a low level of ligand-independent autophosphorylation occurs in the type I kinase; (b) a high level of autophosphorylation
occurs in the type II kinase; (c) both the type III and type I subunits aretrans-phosphorylated by the type II subunit; and (d) the presence of both type I and II kinases complexed with the type III subunit
and dimeric TGFβ1 ligand in a pentameric complex causes maximum phosphorylation of all three receptor subunits. 相似文献
44.
Sequence of the 3''-noncoding and adjacent coding regions of human gamma-globin mRNA. 总被引:4,自引:4,他引:0
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In cloning human fetal globin cDNA in bacterial plasmids, we obtained a recombinant which contained a fragment of gammg-globin cDNA corresponding to the region from amino acid 99 to the poly A. We determined a sequence of 169 nucleotides which included the complete 3' non-coding region of the gamma-globin mRNA. The codon for amino acid 136 was GCA, indicating that this cloned fragment was derived from the Agamma-globin gene. In conjunction with the surrounding sequences, the GCA codon provides the Agamma-species with a unique CTGCAG hexanucleotide that is recognized by the restriction enzyme Pst I. The 3'-untranslated region of the gamma-globin mRNA consists of 90 nucleotides, and shares little homology with that of the human beta-globin mRNA. As in other mammalian mRNAs, a symmetrical sequence and the hexanucleotide AAUAAA are present. 相似文献
45.
The degenerative changes in the spermatids as measured by changes in fine structure abnormalities increased with time following
injection of Cd2+ into rat testis. The spermatids in the twelve hours group appear as peculiarly club shaped and elongated structures with
one or two small but perceptible vacuoles. The subacrosomal area and the space between the nucleus and the middle piece are
seen abnormally dilated. In the 30 day group, the central filaments are the most susceptible unit of 9+2 axoneme complex.
The plasma membrane, the cytoplasmic matrix, the mitochondria of the middle piece and the fibrous sheath appear shrunken,
discontinuous and degenerative. 相似文献
46.
This communication reports on the tolerogenic properties of carboxymethyl cellulose (CMC) as a nonimmunogenic carrier for 2.4 dinitrophenyl (DNP) and the benzylpenicilloyl determinant (BPO). Either normal or primed mice, given an optimal dose of 250 micrograms per animal of DNP CMC, when challenged with an immunogenic form of the hapten as early as 30 min or as late as 21 days thereafter were completely and specifically unresponsive to it. Experimental evidence suggests that this unresponsiveness is not due to suppressor cells. Furthermore, DNP CMC induces tolerance in vivo but fails to do so in vitro under conditions at which other tolerogenic carbohydrate hapten conjugates such as DNP-dextran do. This together with comparative studies of tolerance induction kinetics by DNP CMC and DNP-dextran in vivo led us to conclude that molecular properties other than the epitope density must be attributed to CMC's tolerogenic potential. CMC may also be used as a tolerogenic carrier for BPO with respect to IgE antibody production. Thus, normal or primed mice injected with the BPO CMC conjugate were found specifically unresponsive to a challenge with an immunogenic form of penicillin. 相似文献
47.
The two species of Sarcocystis--S. levinei and S. fusiformis from the water buffalo, Bubalus bubalis, show some ultrastructural similarities in their cyst wall and zoites. The zoites of both species are of about the same size, banana-shaped and have 22 subpellicular microtubules, numerous micronemes, eight rhoptries, a micropore in the region of the micronemes, an elongated mitochondrion, and a nucleus. S. levinei has 200--300 micronemes and S. fusiformis has about 400. The sarcocysts of both species are trabeculated and their cyst walls have cytophaneres containing annulated fibrils and coarse, electron dense granules. The cytophaneres of S. levinei are sloping, with irregular, wavy outlines, whereas S. fusiformis has the cauliflower-type of cytophaneres. This difference in the appearance of the cytophaneres, together with the difference in size of the sarcocysts and their definitive hosts, further confirms that S. levinei and S. fusiformis are two distinct species in the water buffalo. 相似文献
48.
Characterization and molecular cloning of a putative binding protein for heparin-binding growth factors 总被引:5,自引:0,他引:5
D Q Wu M K Kan G H Sato T Okamoto J D Sato 《The Journal of biological chemistry》1991,266(25):16778-16785
A novel Mr 17,000 heparin-binding protein was purified from culture medium conditioned by A431 human epidermoid carcinoma cells. This protein, designated HBp17, was found to bind the heparin-binding peptide growth factors HBGF-1 and HBGF-2 in a noncovalent, reversible manner. In addition HBp17 was found to inhibit the biological activities of both HBGF-1 and HBGF-2. Both the binding and inactivation of HBGF-1 and HBGF-2 by HBp17 were abolished by heparin. Full-length 1163-base pair HBp17 cDNA was cloned and sequenced by using the polymerase chain reaction technique. The deduced primary structure of HBp17 consisted of 234 amino acids including each of five partial peptide sequences obtained from proteolytic fragments of purified HBp17. The encoded protein included a 33-residue N-terminal signal sequence for secretion and a single potential N-linked glycosylation site. No homology with any known protein was found for the deduced primary structure of HBp17. The expression of HBp17 mRNA was found to occur preferentially in normal human keratinocytes and in squamous cell carcinomas. This pattern of HBp17 gene expression suggests that this binding protein for HBGFs 1 and 2 has a physiological role in squamous epithelia. 相似文献
49.
This report describes initial characterization of a 440-kD isoform of brain ankyrin (ankyrinB) representing an alternatively spliced mRNA product of the gene encoding the major isoform of ankyrin in adult human brain (Otto, E., M. Kunimoto, T. McLaughlin, V. Bennett, J. Cell Biology. 114:241-253). Northern and immunoblot analyses indicate that 440-kD ankyrinB includes the spectrin and membrane-binding domains as well as a regulatory domain of the major 220-kD isoform. 440-kD ankyrinB contains, in addition, a sequence of a predicted size of 220 kD which is inserted between the regulatory domain and spectrin/membrane-binding domains. 440-kD ankyrinB has properties expected of a peripherally associated membrane-skeletal protein: it is exclusively present in the particulate fraction of brain homogenates, is extracted with NaOH, and remains associated with Triton-X-100-resistant structures. Expression of 440-kD ankyrinB in rat brain began at birth before other ankyrins could be detected, peaked 10 d after birth, and then decreased progressively to 30% of the maximum in adults. Expression of the 220-kD ankyrinB and ankyrinR (erythroid ankyrin) began approximately 10 d after the 440-kD isoform, increased rapidly between 10 and 15 d after birth, and finally achieved their maximal levels in adults. 440-kD ankyrinB is present in approximately equivalent amounts in all regions of neonatal brain while in adult brain it is present in highest levels in cerebellum and lowest in brain stem. 440-kD ankyrinB was localized by immunofluorescence in regions of neonatal and adult brain containing primarily dendrites and unmyelinated axons. 440-kD ankyrinB thus may play a specialized role in neuronal processes. 相似文献
50.
黑龙江省东宁县山区蜱类的生态调查 总被引:2,自引:0,他引:2
我国东北地区有的蜱种已证实是传播森林脑炎、北亚蜱传斑疹伤寒的媒介。近年来,国内文献又报导了从东北牡丹江林区发现了莱姆病(Lyme Disease)病人,病人都有被婢咬史,并从全沟硬蜱(Ixodes persulcatus)的中 相似文献