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991.
The spindle pole body component Spc97p interacts with the gamma-tubulin of Saccharomyces cerevisiae and functions in microtubule organization and spindle pole body duplication. 总被引:3,自引:1,他引:2 下载免费PDF全文
Previously, we have shown that the gamma-tubulin Tub4p and the spindle pole body component Spc98p are involved in microtubule organization by the yeast microtubule organizing centre, the spindle pole body (SPB). In this paper we report the identification of SPC97 encoding an essential SPB component that is in association with the SPB substructures that organize the cytoplasmic and nuclear microtubules. Evidence is provided for a physical and functional interaction between Tub4p, Spc98p and Spc97p: first, temperature-sensitive spc97(ts) mutants are suppressed by high gene dosage of SPC98 or TUB4. Second, Spc97p interacts with Spc98p and Tub4p in the two-hybrid system. Finally, immunoprecipitation and fractionation studies revealed complexes containing Tub4p, Spc98p and Spc97p. Further support for a direct interaction of Tub4p, Spc98p and Spc97p comes from the toxicity of strong SPC97 overexpression which is suppressed by co-overexpression of TUB4 or SPC98. Analysis of temperature-sensitive spc97(ts) alleles revealed multiple spindle defects. While spc97-14 cells are either impaired in SPB separation or mitotic spindle formation, spc97-20 cells show an additional defect in SPB duplication. We discuss a model in which the Tub4p-Spc98p-Spc97p complex is part of the microtubule attachment site at the SPB. 相似文献
992.
993.
Haase Hannelore Bartel Sabine Karczewski Peter Morano Ingo Krause Ernst-Georg 《Molecular and cellular biochemistry》1996,163(1):99-106
In canine myocardium, the -subunit of the L-type Ca2+ channel is phosphorylated by cAMP dependent protein kinase in vitro as well as in vivo (Haase et al. FEBS Lett 335: 217–222, 1993). We have assessed the identity of the -subunit as well as its in vivo phosphorylation in representative experimental groups of catecholamine-challenged canine hearts. Adrenergic stimulation by high doses of both noradrenaline and isoprenaline induced rapid (within 20 sec) and nearly complete phosphorylation of the Ca2+ channel -subunit. Phosphorylation in vivo was about 4-fold higher as compared to untreated controls. When related to catecholamine-depleted (reserpine-treated) hearts noradrenaline and isoprenaline increased the in vivo phosphorylation of the -subunit even 8-fold. This phosphorylation correlated positively with tissue levels of cAMP, endogenous particulated cAMP-dependent protein kinase (PKA) and the rate of contractile force development dP/dtmax. The results imply the involvement of a PKA-mediated phosphorylation of the Ca2+ channel -subunit in the adrenergic stimulation of intact canine myocardium. 相似文献
994.
Bartel Sabine Karczewski Peter Krause Ernst-Georg 《Molecular and cellular biochemistry》1996,163(1):31-38
The postnatal alterations of the composition of a subunit isoforms (Gic, G i3 Go, and Gq of G proteins, the adenylyl cyclase activity as well as of cAMP-regulated phosphoproteins e.g. troponin and phospholamban were investigated in the ventricular tissue of 1, 7, 30 days old rats. Quantitative immunodetection revealed a 5.7-fold decrease in Gi3 at 30th postnatal day compared with the postnatal day 1 and up to 15-fold at 4 months. The amounts of Gq and G as well as the G subunits were found to be higher in the earlier life period compared to the adult. In contrast, the content of Gs was uneffected by the developmental state. Basal adenylyl cyclase activity (pmoles cAMP/min × mg protein) increased from 30.9 ± 5.0, 36.8 ± 5.0 to 63.9 ± 5.9 at 1st, 7th and 30th postnatal day, respectively. Isoprenaline (100 M) enhanced the activity of adenylyl cyclase from day 1, 7–30 from 46.2 ± 7.0, 79.1 ± 9.2 to 120.5 ± 7.2, respectively. The effects of forskolin and NaF on adenylyl cyclase activity was found to be not influenced within the first postnatal month. Furthermore, a developmentally controlled expression of cardiac troponin I was observed (6-fold from the first to the 28th postnatal day) whereas the level of phospholamban was found to be age-independent.In conclusion, there is an increase in the efficiency of the -adrenergic signal transfer mainly caused by a reduction of the inhibitiory G proteins and a dominance of the Gs-linked pathway in the postnatal rat heart. Furthermore the developmentally controlled expression of troponin I might be of functional importance in the cAMP-supported relaxation. Additionally, altered Gq, Go and G pattern of the developing rat ventricle may play a role in the observed change of -adrenerg-mediated heart contractility as well as in cardiac differentiation and growth processes. 相似文献
995.
996.
Christine Fischer Sabine Schweigert Cord Spreckelsen Friedrich Vogel 《Human genetics》1996,97(2):129-137
We present an overview of the variety of databases and programs that offer substantial aid to medical and molecular geneticists. Databases and expert systems for genetic diseases and birth defects, programs for segregation and linkage analysis, certain DNA and protein sequence databases, and information resources in general for molecular biology are addressed. These systems cannot be used effectively without the newly developed techniques of information exchange based on international computer networks. A short introduction is given to the Internet and to European institutions and organizations that offer help with the aquisition and use of bioinformatic resources. 相似文献
997.
Ingrid Handig Erna Dams Franco Taroni Sabine Van Laere Thierry de Barsy Patrick J. Willems 《Human genetics》1996,97(3):291-293
Deficiency of carnitine palmitoyltransferase type II (CPT II) is a clinically heterogeneous autosomal recessive disorder of lipid metabolism. The most common mutation in the CPT 11 gene is the S113L mutation, which substitutes leucine for serine at amino acid position 113. We studied an inbred family with three affected cousins with CPT II deficiency and found the S113L mutation to be present in a homozygous state in all three patients. Pedigree analysis traced the S 113L mutation back to one common ancestor. Although the patients in this family have an identical genotype at the CPT II locus, their clinical picture ranges from asymptomatic to lethal. 相似文献
998.
999.
Lena Suzuki Jeffrey P. Woessner Hidenobu Uchida† Haruko Kuroiwa Yasuhito Yuasa Sabine Waffenschmidt Ursula W. Goodenough Tsuneyoshi Kuroiwa 《Journal of phycology》2000,36(3):571-583
The cell wall of Chlamydomonas reinhardtii zygotes, which forms rapidly after the fusion of wall-free gametes, provides a tractable system for studying the properties and assembly of hydroxyproline-rich glycoproteins, the major proteinaceous components of green algal and plant cell walls. We report the cloning of the zsp2 gene and the analysis of its ZSP-2 product, a 58.9 kDa polypeptide that is synthesized exclusively by zygotes. The protein contains two (SP)x repeats, establishing it as a member of the cell wall hydroxyproline-rich glycoproteins family. It also contains a 4-fold iteration of an amino acid sequence centered around cysteine residues, a configuration found in both plant and animal lectins. Furthermore, we report four observations on pellicle composition and production. First, cell-free preparations of the pellicle matrix are rich in hydroxyproline, arabinose, and galactose and contain bundles of very long fibrils. Second, glutathione blocks pellicle formation and results in the accumulation of long fibrils in the growth medium. Third, antibody to ZSP-2 also blocks pellicle formation. Fourth, ZSP-2 immunolocalizes to the boundary between the outer layers of the wall proper and the pellicle matrix. These observations are consistent with the possibility that the Cys-rich (glutathione-sensitive) lectin-like domains of ZSP-2 may bind to sugar residues on the long fibrils and anchor them to the cell wall, thereby initiating and maintaining pellicle formation. 相似文献
1000.