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T Schuster

Publications and source records attributed to T Schuster.

At least 55 records · Page 3Linked to original sources
PubMed1997

The regulatory subunit of protein kinase CK2 is a specific A-Raf activator.

Two protein kinases that are involved in proliferation and oncogenesis but so far were thought to be functionally independent are Raf and CK2. The Raf signaling pathway is known to play a critical role in such fundamental biological processes as cellular proliferation and differentiation. Abnormal activation of this pathway is potentially oncogenic. Protein kinase CK2 exhibits enhanced levels in solid human tumors and proliferating tissue. In a two-hybrid screen of a mouse-embryo cDNA library we detected an interaction between A-Raf and CK2beta subunit. This binding was specific, as no interaction between CK2beta and B-Raf or c-Raf-1 was observed. Regions critical for this interaction were localized between residues 550 and 569 in the A-Raf kinase domain. A-Raf kinase activity was enhanced 10-fold upon coexpression with CK2beta in Sf9 cells. The alpha subunit of CK2 abolishes this effect. This is the first demonstration of both a direct Raf-isoform-specific activation and a regulatory role for CK2beta independent of the CK2alpha subunit. The present data thus link two different protein kinases that were thought to work separately in the cell.

Animals↗
PubMed1996

The mouse poly(C)-binding protein exists in multiple isoforms and interacts with several RNA-binding proteins.

The murine poly(C)-binding protein (mCBP) was previously shown to belong to the group of K-homology (KH) proteins by virtue of its homology to hnRNP-K. We have isolated cDNA-splice variants of mCBP which differ by two variable regions of 93 bp and/or 39 +/- 3 bp respectively. Both variable regions are located between the second and third KH-domain of mCBP. The characterization of a partial genomic clone enabled us to propose a model for the generation of the second variable region by the use of a putative alternative splice signal. The mCBP mRNA is expressed ubiquitously and the protein is found predominantly in the nucleus with the exception of the nucleoli. We have identified five proteins which interact with mCBP in the yeast two hybrid system: mouse y-box protein 1 (msy-1), y-box-binding protein, hnRNP-L, filamin and splicing factor 9G8. The interaction between mCBP and splicing factor 9G8 was confirmed in vivo. These results suggest a function of mCBP in RNA metabolism.

Animals↗
PubMed1996

Testicular germ cell tumors in patients with human immunodeficiency virus infection.

BACKGROUND: There has been evidence of a higher incidence of testicular germ cell tumors (GCT) in human immunodeficiency virus (HIV)-seropositive men than in the non HIV-infected male population. Most authors recommend standard therapy for HIV-positive patients with GCT but the immumosuppressive effects of chemotherapy and/or radiotherapy must be considered. METHODS: The records of all patients in whom testicular cancer was diagnosed and/or treated at a single institution between January 1986 and July 1995 were reviewed with regard to HIV seropositivity. Tumor histology, initial staging, treatment, and the patients' outcomes were analyzed in connection with a review of the literature. RESULTS: Six patients with GCT and documented HIV seropositivity at the time of tumor diagnosis (four homosexuals, one bisexual, and one heterosexual former intravenous drug abuser) of 192 documented cases of testicular cancer are reported. In addition, 1 patient proved to be HIV seropositive 34 months after completing chemotherapy (vinblastine, ifosfamide, and cisplatin) for Stage IIB (minimal disease) seminoma. Intensified platinum-based chemotherapy was administered to two patients with clinical Stage IIIC (advanced disease) nonseminomatous germ cell tumors (NSGCT). Both patients achieved a transient partial response but suffered from progressive HIV disease and died 24 and 7 months, respectively, after orchiectomy. One patient with Stage IIIA (moderate disease) seminoma received four courses of chemotherapy (etoposide, ifosfamide, and cisplatin) and has remained in complete remission for 40 months. One patient with bilateral Stage I seminoma underwent adjuvant radiotherapy but was lost to follow-up. One patient with clinical Stage IIA (minimal disease) NSGCT refused any further treatment after hemiorchiectomy, but four courses of chemotherapy (cisplatin, etoposide and bleomycin) had to be given 32 months later because of symptomatic abdominal disease. A partial remission was obtained and there was no evidence of active tumor 16 months after the completion of chemotherapy. A retroperitoneal lymph node dissection was performed in 1 patient with Stage I NSGCT who was free of disease 111 months after diagnosis. The Centers for Disease Control classification for HIV infection and acquired immune deficiency syndrome (AIDS) did not change after therapy in two patients, whereas three patients suffered from progressive HIV disease. CONCLUSIONS: HIV infection should be considered in patients with testicular cancer who belong to an urban population. Oncologic therapy based on a patient's individual situation is recommended.

Adult↗
PubMed1996

Chronic recurrent multifocal osteomyelitis (CRMO).

Pathogenesis of CRMO still remains unknown. Characteristic, but not pathognomonic for this syndrome are clinical course (age, sex, chronic recurrent, intermittent course), radiological findings (metaphyseal lesions), histology (chronic osteomyelitis without colliquation) and microbiological results (lack of pathogen, infectious agents). Favorable, self-limited long-term prognosis of CRMO has been assumed. Antibiotics provide no improvement. Course, severity and recurrency can be influenced positively by antiphlogistic substances, although this has not yet been proved. Whether surgical intervention beyond biopsies might cause improvement on the follow-up is unknown. Our experience (4 cases), and the literature demonstrate great clinical importance that unusual types of osteomyelitis (OM) can be within the differential diagnosis of multifocal osteolytic changes.

Adolescent↗
PubMed1996

EGT2 gene transcription is induced predominantly by Swi5 in early G1.

In a screen for cell cycle-regulated genes in the yeast Saccharomyces cerevisiae, we have identified a gene, EGT2, which is involved in cell separation in the G1 stage of the cell cycle. Transcription of EGT2 is tightly regulated in a cell cycle-dependent manner. Transcriptional levels peak at the boundary of mitosis and early G1 The transcription factors responsible for EGT2 expression in early G1 are Swi5 and, to a lesser extent, Ace2. Swi5 is involved in the transcriptional activation of the HO gene during late G1 and early S phase, and Ace2 induces CTS1 transcription during early and late G1 We show that Swi5 activates EGT2 transcription as soon as it enters the nucleus at the end of mitosis in a concentration-dependent manner. Since Swi5 is unstable in the nucleus, its level drops rapidly, causing termination of EGT2 transcription before cells are committed to the next cell cycle. However, Swi5 is still able to activate transcription of HO in late G1 in conjunction with additional activators such as Swi4 and Swi6.

Amino Acid Sequence↗
PubMed1995

Insertional mutation of the motor endplate disease (med) locus on mouse chromosome 15.

Homozygous transgenic mice from line A4 have an early-onset progressive neuromuscular disorder characterized by paralysis of the rear limbs, muscle atrophy, and lethality by 4 weeks of age. The transgene insertion site was mapped to distal chromosome 15 close to the locus motor endplate disease (med). The sequence of mouse DNA flanking the insertion site junctions was determined. A small (< 20 kb) deletion was detected at the insertion site, with no evidence of additional rearrangement of the chromosomal DNA. Noncomplementation of the transgene-induced mutation and med was demonstrated in a cross with medJ/+mice. The new allele is designated medTgNA4Bs (medtg). The homologous human locus MED was assigned to chromosome 12. Synaptotagmin 1 and contactin 1 were eliminated as candidate genes for the med mutation. The transgene-induced allele provides molecular access to the med gene, whose function is required for synaptic transmission at the neuromuscular junction and long-term survival of cerebellar Purkinje cells.

Animals↗
PubMed1994

The tetratricopeptide repeat-domain of the PAS10 protein of Saccharomyces cerevisiae is essential for binding the peroxisomal targeting signal-SKL.

The PAS10 gene was found in a two-hybrid screen for the isolation of genes encoding proteins which interact with the C-terminal peroxisomal targeting signal -SKL. The PAS10 protein is known to be involved in import of proteins into peroxisomes and to contain a tetratricopeptide repeat (TPR) domain. All TPR-containing proteins involved in diverse processes like mitosis or RNA-synthesis share the ability to interact with other proteins. Here we show that the PAS10 protein interacts in vivo with the C-terminal peroxisomal targeting signal. The part essential for this interaction contains the complete tetratricopeptide repeat domain.

Amino Acid Sequence↗
PubMed1994

Differential expression of synaptophysin and synaptoporin during pre- and postnatal development of the rat hippocampal network.

The closely related synaptic vesicle membrane proteins synaptophysin and synaptoporin are abundant in the hippocampal formation of the adult rat. But the prenatal hippocampal formation contains only synaptophysin, which is first detected at embryonic day 17 (E17) in perikarya and axons of the pyramidal neurons. At E21 synaptophysin immunoreactivity extends into the apical dendrites of these cells and in newly formed terminals contacting these dendrites. The transient presence of synaptophysin in axons and dendrites suggests a functional involvement of synaptophysin in fibre outgrowth of developing pyramidal neurons. Synaptoporin expression parallels the formation of dentate granule cell synaptic contacts with pyramidal neurons: the amount of hippocampal synaptoporin, determined in immunoblots and by synaptoporin immunostaining of developing mossy fibre terminals; increases during the first postnatal week. Moreover, in the adult, synaptoporin is found exclusively in the mossy fibre terminals present in the hilar region of the dentate gyrus and the regio inferior of the cornu ammonis. In contrast, synaptophysin is present in all synaptic fields of the hippocampal formation, including the mossy fibre terminals, where it colocalizes with synaptoporin in the same boutons. Our data indicate that granule neuron terminals differ from all other terminals of the hippocampal formation by the presence of both synaptoporin and synaptophysin. This difference, observed in the earliest synaptic contacts in the postnatal hippocampus and persisting into adult life, suggests distinct functions of synaptoporin in these nerve terminals.

Animals↗