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M Matzner

Publications and source records attributed to M Matzner.

15 recordsLinked to original sources
PubMed1999

Drainin required for membrane fusion of the contractile vacuole in Dictyostelium is the prototype of a protein family also represented in man.

The contractile vacuole expels water by forming a channel with the plasma membrane and thus enables cells to survive in a hypo-osmotic environment. Here we characterize drainin, a Dictyostelium protein involved in this process, as the first member of a protein family represented in fission yeast, Caenorhabditis elegans and man. Gene replacement in Dictyostelium shows that drainin acts at a checkpoint of channel formation between the contractile vacuole and the plasma membrane. A green fluorescent protein fusion of drainin localizes specifically to the contractile vacuole and rescues its periodic discharge in drainin-null cells. Drainin is a peripheral membrane protein, requiring a short hydrophobic stretch in its C-terminal region for localization and function. We suggest that drainin acts in a signaling cascade that couples a volume-sensing device in the vacuolar membrane to the membrane fusion machinery.

Amino Acid Sequence↗
PubMed1998

Interaptin, an actin-binding protein of the alpha-actinin superfamily in Dictyostelium discoideum, is developmentally and cAMP-regulated and associates with intracellular membrane compartments.

In a search for novel members of the alpha-actinin superfamily, a Dictyostelium discoideum genomic library in yeast artificial chromosomes (YAC) was screened under low stringency conditions using the acting-binding domain of the gelation factor as probe. A new locus was identified and 8.6 kb of genomic DNA were sequenced that encompassed the whole abpD gene. The DNA sequence predicts a protein, interaptin, with a calculated molecular mass of 204,300 D that is constituted by an actin-binding domain, a central coiled-coil rod domain and a membrane-associated domain. In Northern blot analyses a cAMP-stimulated transcript of 5.8 kb is expressed at the stage when cell differentiation occurs. Monoclonal antibodies raised against bacterially expressed interaptin polypeptides recognized a 200-kD developmentally and cAMP-regulated protein and a 160-kD constitutively expressed protein in Western blots. In multicellular structures, interaptin appears to be enriched in anterior-like cells which sort to the upper and lower cups during culmination. The protein is located at the nuclear envelope and ER. In mutants deficient in interaptin development is delayed, but the morphology of the mature fruiting bodies appears normal. When starved in suspension abpD- cells form EDTA-stable aggregates, which, in contrast to wild type, dissociate. Based on its domains and location, interaptin constitutes a potential link between intracellular membrane compartments and the actin cytoskeleton.

Actinin↗
PubMed1998

Microtubule-mediated centrosome motility and the positioning of cleavage furrows in multinucleate myosin II-null cells.

To study centrosome motility and the interaction of microtubules with the cell cortex in mitotic, post-mitotic and interphase cells, (alpha)-tubulin was tagged in Dictyostelium discoideum with green fluorescent protein. Multinucleate cells formed by myosin II-null mutants proved to be especially suited for the analysis of the control of cleavage furrow formation by the microtubule system. After docking of the mitotic apparatus onto the cell cortex during anaphase, the cell surface is activated to form ruffles on top of the asters of microtubules that emanate from the centrosomes. Cleavage furrows are initiated at spaces between the asters independently of the positions of spindles. Once initiated, the furrows expand as deep folds without a continued connection to the microtubule system. Occurrence of unilateral furrows indicates that a closed contractile ring is dispensable for cytokinesis in Dictyostelium. The progression of cytokinesis in the multinucleate cells underlines the importance of proteins other than myosin II in specifying a cleavage furrow. The analysis of centrosome motility suggests a major role for a minus-end directed motor protein, probably cytoplasmic dynein, in applying traction forces on guiding microtubules that connect the centrosome with the cell cortex.

Anaphase↗
PubMed1996

Myristoylated and non-myristoylated forms of the pH sensor protein hisactophilin II: intracellular shuttling to plasma membrane and nucleus monitored in real time by a fusion with green fluorescent protein.

Hisactophilins are myristoylated proteins that are rich in histidine residues and known to exist in Dictyostelium cells in a plasma membrane-bound and a soluble cytoplasmic state. Intracellular translocation of these proteins in response to pH changes was monitored using hisactophilin fusions with green fluorescent protein (GFP) and confocal laser scanning microscopy. Both the normal and a mutated non-myristoylated fusion protein shuffled within the cells in a pH-dependent manner. After lowering the pH, these proteins translocated within minutes between the cytoplasm, the plasma membrane and the nucleus. The role of histidine clusters on the surface of hisactophilin molecules in binding of the proteins to the plasma membrane and in their transfer to the nucleus is discussed on the basis of a pH switch mechanism.

Actins↗
PubMed1996

Expression of fibulin-2 by fibroblasts and deposition with fibronectin into a fibrillar matrix.

The extracellular matrix protein fibulin-2 was shown to be a typical product of cultured human and mouse fibroblasts by several immunological assays. It is secreted and deposited in cells and tissues as a disulfide-bonded oligomer identical in size to the previously described recombinant fibulin-2. Most of the fibroblast fibulin-2 is deposited into a dense fibrillar meshwork which requires treatment with EDTA and/or 6 M urea for solubilization. Fibulin-2 and fibronectin are synthesized at equivalent levels and both colocalize in the fibrils as shown by immunofluorescence. Metabolic labelling and pulse-chase studies demonstrated fibulin-2 oligomers in detergent extracts of cells and their rapid translocation to extracellular EDTA-sensitive assembly forms. Unlike for fibronectin and fibulin-1 only a little fibulin-2 was found in the cell culture medium. Immunogold staining of confluent human fibroblasts showed localization of fibulin-2 to a fine meshwork or bundles of amorphous microfibrils in the matrix. This also demonstrated a distinct colocalization of fibulin-2 and fibronectin at the electron microscope level, indicating that the interaction between these two protein shown in in vitro assays may also exist in situ. No distinct colocalization of both proteins could, however, be observed with cross-striated fibrils of collagen I and collagen VI microfibrils.

Animals↗
PubMed1995

The Cdc31p-binding protein Kar1p is a component of the half bridge of the yeast spindle pole body.

KAR1 has been identified as an essential gene which is involved in karyogamy of mating yeast cells and in spindle pole body duplication of mitotic cells (Rose, M. D., and G. R. Fink. 1987. Cell. 48:1047-1060). We investigated the cell cycle-dependent localization of the Kar1 protein (Kar1p) and its interaction with other SPB components. Kar1p is associated with the spindle pole body during the entire cell cycle of yeast. Immunoelectron microscopic studies with anti-Kar1p antibodies or with the monoclonal antibody 12CA5 using an epitope-tagged, functional Kar1p revealed that Kar1p is associated with the half bridge or the bridge of the spindle pole body. Cdc31p, a Ca(2+)-binding protein, was previously identified as the first component of the half bridge of the spindle pole body (Spang, A., I. Courtney, U. Fackler, M. Matzner, and E. Schiebel. 1993. J. Cell Biol. 123:405-416). Using an in vitro assay we demonstrate that Cdc31p specifically interacts with a short sequence within the carboxyl terminal half of Kar1p. The potential Cdc31p-binding sequence of Kar1p contains three acidic amino acids which are not found in calmodulin-binding peptides, explaining the different substrate specificities of Cdc31p and calmodulin. Cdc31p was also able to bind to the carboxy terminus of Nuflp/Spc110p, another component of the SPB (Kilmartin, J. V., S. L. Dyos, D. Kershaw, and J. T. Finch. 1993. J. Cell Biol. 123:1175-1184). The association of Kar1p with the spindle pole body was independent of Cdc31p. Cdc31p, on the other hand, was not associated with SPBs of kar1 cells.

Base Sequence↗
PubMed1993

P-glycoprotein expression in human plasma cell myeloma: correlation with prior chemotherapy.

Multidrug-resistant (MDR) myeloma patients failing chemotherapy may express P-glycoprotein (PGP), which serves as an efflux pump protecting the neoplastic cells. Unknown is whether PGP expression might relate to prior cytotoxic drug exposure. To address this question, we studied 106 consecutive bone marrow samples from 104 myeloma patients with samples studied either before or after therapy and at the time of relapse. We performed an established immunocytochemical assay of PGP using an MDR-1-specific monoclonal antibody and correlated PGP status with prior chemotherapy dosage. Myeloma patients with no prior therapy had a low incidence of PGP expression (6%, 3/47), whereas those receiving chemotherapy had a significantly higher incidence (43%, 21/49) (P < .0001). A substantially higher incidence of PGP expression (50%, 83%, respectively) occurred when the total vincristine dose exceeded 20 mg and when doxorubicin exceeded 340 mg. In the 11 patients who received both high vincristine and doxorubicin dosages (> 20 mg, > 340 mg total dose) there was 100% incidence of PGP expression in the tumor cells. These data provided the basis for a predictive mathematical model from which dose-related PGP expression normograms were generated. Time with myeloma for PGP-negative patients (mean 33 months) had overlapping confidence limits with PGP-positive patients (mean 42 months), suggesting that disease duration was not a significant variable. PGP expression did not correlate with other clinical factors or immunophenotypic factors. Our findings indicate a strong correlation between PGP expression in myeloma and past chemotherapy in myeloma, in particular, related to prior exposure to the natural product agents vincristine and doxorubicin. Additionally, the proportion of PGP-positive plasma cells was significantly higher in the doxorubicin-treated patients than the nondoxorubicin-treated patients (87.7% v 65.17%; P = .013). Combined high vincristine and doxorubicin total dosage appear highly predictive of PGP expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

The calcium-binding protein cell division cycle 31 of Saccharomyces cerevisiae is a component of the half bridge of the spindle pole body.

Cdc31 mutants of Saccharomyces cerevisiae arrest at the nonpermissive temperature with large buds, G2 DNA content and, a single, abnormally large spindle pole body (SPB) (Byers, B. 1981. Molecular Genetics in Yeast. Alfred Benzon Symposium. 16:119-133). In this report, we show that the CDC31 gene product is essential for cell viability. We demonstrate that purified CDC31 protein binds Ca2+ and that this binding is highly specific. Taken together, three lines of evidence indicate that CDC31 is a component of the SPB. First, CDC31 cofractionates with enriched preparations of SPBs. Second, immunofluorescence staining indicates that CDC31 colocalizes with a known SPB component. Third, immunoelectron microscopy with whole cells and with isolated SPBs reveals that CDC31 is localized to the half bridge of the SPB, which lies immediately adjacent to the SPB plaques. CDC31 was detected mainly at the cytoplasmic side of the half bridge and, therefore, defines a further substructure of the SPB. We suggest that CDC31 is a member of a family of calcium-binding, centrosome-associated proteins from a phylogenetically diverse group of organisms.

Animals↗
PubMed1992

Antitumor activity and clinical pharmacology of sulofenur in ovarian cancer.

BACKGROUND: Sulofenur is a diarylsulfonylurea with demonstrated antitumor activity in patients with advanced epithelial ovarian cancer refractory to standard chemotherapy. The dose-limiting toxic effects observed in phase I clinical trials have been anemia and methemoglobinemia, resulting in cyanosis. PURPOSE: The purposes of this study were to further define the response rate, toxic effects, and pharmacokinetics and pharmacodynamics of sulofenur in patients with advanced ovarian cancer. METHODS: We conducted a phase II trial of sulofenur at a dose of 800 mg/m2 per day in 35 patients with stage III or IV ovarian cancer refractory to standard chemotherapy. Pharmacokinetics and pharmacodynamics were analyzed by comparing sulofenur parent and metabolite plasma levels with methemoglobin levels. RESULTS: Partial responses lasting 6.5-18 weeks occurred in four (15%; 95% confidence interval = 4%-35%) of the 26 patients assessable for response. In addition, 42% (11) of the assessable patients had prolonged stable disease (median, 20 weeks). The first nine patients received sulofenur as a daily oral dose for 14 days, with a 21-day treatment cycle. However, they developed substantial anemia and methemoglobinemia. As a result, the next 26 patients received sulofenur daily for 5 days followed by 2 days of rest for 3 consecutive weeks, with a 28-day treatment cycle (5/2-day schedule). Preclinical models predicted that 2 days of rest would decrease toxicity while maintaining antitumor activity. Patients treated with the 5/2-day schedule had relatively less severe anemia and methemoglobinemia and needed fewer red blood cell transfusions (31% versus 78% of patients), but 31% still required dose reductions because of these toxic effects. The hydroxy and keto metabolites of sulofenur had prolonged plasma half-lives relative to the parent compound, and the difference was statistically significant. In addition, the correlations of metabolite concentrations with methemoglobin levels were higher than the correlation of sulofenur concentrations with methemoglobin levels, and those differences were statistically significant. CONCLUSION: We conclude that sulofenur has modest clinical activity in heavily pretreated patients with ovarian cancer. IMPLICATIONS: The toxic effects of anemia and methemoglobinemia may limit the ultimate clinical utility of diarylsulfonylureas until less toxic derivatives with alternate metabolic pathways can be identified.

Adult↗
PubMed1992

Neural cell adhesion molecule-positive peripheral T-cell lymphoma: a rare variant with a propensity for unusual sites of involvement.

A distinct subset of patients with peripheral T-cell lymphoma (PTCL) is described which reacts with Leu-19 (CD56), an antibody that has been shown to identify the neural cell adhesion molecule (NCAM). These NCAM-positive PTCL patients (11 of a series of 46 PTCL; 24%) exhibited a striking predilection for unusual anatomic sites of involvement: central nervous system (36%), muscle (18%), gastrointestinal tract, and nasopharynx (27% each). Additional extranodal sites of involvement included the pituitary, thyroid, parathyroids, adrenals, and pancreas. The NCAM-positive subset also exhibited a characteristic phenotypic profile, with significantly lower expression of CD3 and CD5 compared with the NCAM-negative group. RNA transcripts consistent with the NCAM gene were detected in tissue samples from five Leu-19-positive cases using a reverse transcriptase-polymerase chain reaction assay, supporting the idea that Leu-19 recognizes NCAM in these patient samples. This suggests that the expression of the NCAM plays a role in the behavior and localization of lymphomas. Because of the unique clinical and phenotypic characteristics of this group it may be designated as "NCAM-positive peripheral T-cell lymphoma."

Adult↗
PubMed1992

Diffuse small cleaved-cell lymphoma: a heterogeneous disease with distinct immunobiologic subsets.

PURPOSE AND METHODS: Diffuse small cleaved-cell lymphoma (DSCL) is a relatively uncommon non-hodgkin's lymphoma (NHL) in the United States and has not been the subject of recent in-depth study of factors predictive of outcome. It is unique among the NHL of intermediate grade because there is no evidence of a curable subset of patients. To investigate whether any laboratory data might predict outcome, we studied 33 cases collected during a 12-year period and correlated morphology, immunohistochemistry, and serum lactate dehydrogenase (LDH) with clinical data and outcome. RESULTS: We found that proliferative rate (Ki-67), cell lineage (T v B cell), and serum LDH were associated with significant differences in survival. A Ki-67 value greater than or equal to 20% was associated with a median survival of 20 months compared with 80 months for lower values (P = .0002); patients with tumors of T-cell lineage had a median survival of 20 months compared with 40 months for those with B-cell neoplasms (P = .0143); and a serum LDH greater than 225 IU/L was associated with a median survival of 8 months compared with 40 months for lower LDH levels (P = .0004). Blastoid morphology was also linked to a trend toward poor outcome (P = .08). Neither a history of low-grade lymphoma nor the presence of residual immunologically detectable follicles influenced outcome (P = .93 and .97, respectively). CONCLUSION: We conclude that high Ki-67, high LDH, and T-cell lineage each identify DSCL patients with poor outcome.

Adult↗
PubMed1990

[NMR tomography compared to skeletal scintigraphy after traumatic vertebral body fractures].

MRI and scintigraphy were compared in 73 patients with 104 vertebral fractures aged between three days and 64 months. MRI was performed at 0.5 Tesla and 1.5 Tesla using T1- and T2-weighted spin-echo sequences. Isotope uptake was divided into four grades (normal, mild, moderate and marked increase). 92% of cases aged 0-6 months showed increased signal intensity on T2 sequences. This finding reflects edema in the bone. All these cases showed moderate or markedly increased uptake in 86%. The increased signal intensity in T2 spin-echo images provides a criterion for differentiating new from old fractures. The identification of normal fatty marrow in 91% of fractured vertebrae provides an important means for distinguishing traumatic from neoplastic fractures. One can also demonstrate bleeding, fatty change and sclerotic bone. MRI is less sensitive than scintigraphy, but more specific in following the posttraumatic healing process.

Adolescent↗
PubMed1975

Autotransfusion of 3H-cytidine-labelled blood lymphocytes in patients with Hodgkin's disease and non-Hodgkin patients. II. Exchangeable lymphocyte pools.

The dilution in the circulating blood of lymphocytes lablled in vitro with 3H-cytidine was examined after autotransfusion in 9 patients with Hodgkin's disease (HD) stage II A-IV B, 5 of whom were untreated; in 2 untreated patients with carcinoma, and in 1 treated patient with scleroderma. The blood transit time of exchangeable lymphocytes was 37 +/- 18 min in the patients with HD and 26 +/- 6 min in the other patients. The proportion of exchangeable (recirculating) small blood lymphocytes was 39-84% in HD and 81-91% in the carcinoma patients. The relation between the size of the circulating pool of small blood lymphocytes and the total exchangeable (recirculating) lymphocyte pool was 1:20 to 1:30 in HD and 1:29 to 1:34 in the other patients. The absolute size of the recirculating pool of lymphocytes was 46-90 times 10(9) cells in HD and 100-150 times 10(9) cells in the carcinoma patients.

Adult↗