The Drosophila tissue polarity gene inturned acts cell autonomously and encodes a novel protein

Mutations in the inturned (in) gene result in abnormal wing hair polarity and in many wing cells forming two or more hairs instead of the normal single hair. We have generated genetic mosaics in a number of different experiments and find that the in gene is required in all regions of the wing and that it functions in a cell autonomous fashion. We report the molecular cloning of the in gene, the molecular mapping of in mutations and the isolation and sequencing of an in cDNA clone. The in gene encodes a novel protein whose sequence suggests it will be membrane bound. The ability of an in cDNA, the expression of which is driven by the basal activity of the hsp70 promoter to rescue an in mutation suggests that patterned expression of in is unlikely to play a role in the function of the gene.

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Chs1p and Chs3p, two proteins involved in chitin synthesis, populate a compartment of the Saccharomyces cerevisiae endocytic pathway.

Molecular Biology of the Cell ◽

10.1091/mbc.7.12.1909 ◽

1996 ◽

Vol 7 (12) ◽

pp. 1909-1919 ◽

Cited By ~ 104

Author(s):

M Ziman ◽

J S Chuang ◽

R W Schekman

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Endocytic Pathway ◽

Chitin Synthase ◽

Cell Fractionation ◽

Cell Wall Polysaccharide ◽

Chitin Synthesis ◽

A Cell ◽

Steady State Levels ◽

Membrane Bound

In Saccharomyces cerevisiae, the synthesis of chitin, a cell-wall polysaccharide, is temporally and spatially regulated with respect to the cell cycle and morphogenesis. Using immunological reagents, we found that steady-state levels of Chs1p and Chs3p, two chitin synthase enzymes, did not fluctuate during the cell cycle, indicating that they are not simply regulated by synthesis and degradation. Previous cell fractionation studies demonstrated that chitin synthase I activity (CSI) exists in a plasma membrane form and in intracellular membrane-bound particles called chitosomes. Chitosomes were proposed to act as a reservoir for regulated transport of chitin synthase enzymes to the division septum. We found that Chs1p and Chs3p resided partly in chitosomes and that this distribution was not cell cycle regulated. Pulse-chase cell fractionation experiments showed that chitosome production was blocked in an endocytosis mutant (end4-1), indicating that endocytosis is required for the formation or maintenance of chitosomes. Additionally, Ste2p, internalized by ligand-induced endocytosis, cofractionated with chitosomes, suggesting that these membrane proteins populate the same endosomal compartment. However, in contrast to Ste2p, Chs1p and Chs3p were not rapidly degraded, thus raising the possibility that the temporal and spatial regulation of chitin synthesis is mediated by the mobilization of an endosomal pool of chitin synthase enzymes.

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Lithium-induced modiphication of the physicochemical state of membrane proteins and lipids in human erythrocytes

Proceedings of the National Academy of Sciences of Belarus Biological Series ◽

10.29235/1029-8940-2021-66-3-295-301 ◽

2021 ◽

Vol 66 (3) ◽

pp. 295-301

Author(s):

G. P. Zubritskaya ◽

E. I. Slobozhanina

Keyword(s):

Lithium Salt ◽

Test System ◽

Human Erythrocytes ◽

Lithium Ions ◽

Physicochemical State ◽

A Cell ◽

Cell Test ◽

Membrane Bound ◽

Toxic Concentrations

The effect of various concentrations of lithium sulfate on human erythrocytes in vitro has been studied. It has been shown that the effect of lithium salt in maximum pharmacological and toxic concentrations on cells leads to a modification of the physicochemical state of membrane-bound proteins and lipids. It was found that in human erythrocytes exposed to lithium ions, there is a decrease in the activity of membrane-bound acetylcholinesterase and methgemoglobin reductase, as well as a change in the microviscosity of the lipid bilayer of membranes. The results obtained can be used to create a cell test system for assessing the toxicity of lithium compounds.

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A second melanotransferrin gene (MTf2) and a novel protein isoform: explanation for the membrane-bound and soluble forms of melanotransferrin?

FEBS Letters ◽

10.1016/s0014-5793(02)02248-2 ◽

2002 ◽

Vol 512 (1-3) ◽

pp. 350-352 ◽

Cited By ~ 12

Author(s):

Eric Sekyere ◽

Michael R Food ◽

Des R Richardson

Keyword(s):

Membrane Bound ◽

Protein Isoform ◽

Novel Protein

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rasp, a putative transmembrane acyltransferase, is required for Hedgehog signaling

Development ◽

10.1242/dev.129.4.843 ◽

2002 ◽

Vol 129 (4) ◽

pp. 843-851 ◽

Cited By ~ 9

Author(s):

Craig A. Micchelli ◽

Inge The ◽

Erica Selva ◽

Vladic Mogila ◽

Norbert Perrimon

Keyword(s):

Hedgehog Signaling ◽

Transmembrane Protein ◽

Post Translational Modification ◽

Protein Levels ◽

Lethal Mutations ◽

Segment Polarity ◽

Invertebrate Development ◽

Membrane Bound ◽

Segment Polarity Gene ◽

Polarity Gene

Members of the Hedgehog (Hh) family encode secreted molecules that act as potent organizers during vertebrate and invertebrate development. Post-translational modification regulates both the range and efficacy of Hh protein. One such modification is the acylation of the N-terminal cysteine of Hh. In a screen for zygotic lethal mutations associated with maternal effects, we have identified rasp, a novel Drosophila segment polarity gene. Analysis of the rasp mutant phenotype, in both the embryo and wing imaginal disc demonstrates that rasp does not disrupt Wnt/Wingless signaling but is specifically required for Hh signaling. The requirement of rasp is restricted only to those cells that produce Hh; hh transcription, protein levels and distribution are not affected by the loss of rasp. Molecular analysis reveals that rasp encodes a multipass transmembrane protein that has homology to a family of membrane bound O-acyl transferases. Our results suggest that Rasp-dependent acylation is necessary to generate a fully active Hh protein.

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A single frizzled protein has a dual function in tissue polarity

Development ◽

10.1242/dev.120.7.1883 ◽

1994 ◽

Vol 120 (7) ◽

pp. 1883-1893 ◽

Cited By ~ 13

Author(s):

R.E. Krasnow ◽

P.N. Adler

Keyword(s):

Dual Function ◽

Protein Species ◽

Hsp70 Promoter ◽

Tissue Polarity ◽

Genetic Mosaic ◽

Single Protein ◽

Genetic Epistasis ◽

Pupal Wing ◽

Separate Protein ◽

Transgenic Flies

The Drosophila frizzled (fz) gene is required for the development of normal tissue polarity in the epidermis. Genetic epistasis experiments argue that fz is at the top of a regulatory hierarchy that controls the subcellular site for prehair initiation within the cells of the pupal wing (Wong and Adler, 1993; J. Cell Biol. 123, 209–221). Genetic mosaic experiments indicate that fz has both cell autonomous and cell non-autonomous functions that are separately mutable (Vinson and Adler, 1987; Nature 329, 549–551). Two species of fz mRNA have been identified, raising the question as to whether the two functions are provided by a single protein or by two separate protein species. We generated transgenic flies that express each of these mRNAs under the control of an hsp70 promoter. Only one of the transgenes (hsfzI) showed any fz activity. At 29 degrees C, the hsfzI transgene provided almost complete rescue of a null fz mutation, indicating that the protein encoded by this cDNA can fulfill both fz functions. Overexpression of the hsfzI transgene resulted in two distinct tissue polarity phenotypes depending on the time of heat shock.

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Article Commentary: Fas and Cancer

Clinical medicine Ear nose and throat ◽

10.4137/cment.s3147 ◽

2010 ◽

Vol 3 ◽

pp. CMENT.S3147

Author(s):

Kamal-Eldin Ahmed Abou-Elhamd

Keyword(s):

Flow Cytometry ◽

Cell Death ◽

Surface Protein ◽

Cell Surface Protein ◽

Active Process ◽

Activated Lymphocytes ◽

A Cell ◽

Membrane Bound ◽

Immunohistochemical Methods ◽

Fas L

Apoptosis is an active process of programmed cell death. Fas is a cell-surface protein which is expressed on activated lymphocytes and known as CD95, TNFRSF6 or APO-1. Fas-L is ligand of Fas and known as CD95 LG or TNFSF6. Apoptosis or cell death is a result of binding of Fas-L to Fas which is expressed on the surfaces of these cells. Cancer cells escape this binding by overexpression of Fas-L or down expression of Fas. Fas and Fas-L exist in membrane bound and soluble forms. The serum level of sFas and sFas-L can be evaluated by immunostaining, immunohistochemical methods, immunofluorescence, flow cytometry and Western blotting. Head and neck squamous cell carcinoma diagnosis, staging and prognosis can be evaluated early and accurately by sFas and sFas-L expression levels detection.

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Characterization of neutral endopeptidase 24.11 in dog glomeruli

Biochemical Journal ◽

10.1042/bj2910773 ◽

1993 ◽

Vol 291 (3) ◽

pp. 773-779 ◽

Cited By ~ 15

Author(s):

C Landry ◽

P Santagata ◽

W Bawab ◽

M C Fournié-Zaluski ◽

B P Roques ◽

...

Keyword(s):

Cell Surface ◽

Brush Border ◽

Neutral Endopeptidase ◽

Glycosylation Pattern ◽

Electrophoretic Mobilities ◽

Mammalian Tissues ◽

Dog Kidney ◽

A Cell ◽

Membrane Bound ◽

Triton X

Neutral endopeptidase (NEP; also known as neprilysin and enkephalinase; EC 3.4.24.11) is a cell-surface metallopeptidase that is present in many mammalian tissues. It is particularly abundant on the brush-border membranes of the kidney proximal tubule. In this paper, the presence of NEP in purified glomeruli from dog kidney was assessed by measuring phosphoramidon- and thiorphan-sensitive [D-Ala2,Leu5]enkephalin-degrading activity. Using this assay, the Km and kcat. of the glomerular enzyme were found to be identical to those of the tubular enzyme. By Western blotting the apparent M(r) of the glomerular enzyme was found to be 104,000, compared with 94,000 for the tubular enzyme. This might be due to a different glycosylation pattern, since endoglycosidase F treatment of NEP obtained from both tissues yielded deglycosylated enzymes with similar electrophoretic mobilities. The glomerular enzyme also appears to be membrane-bound, since it was retained in the detergent-rich phase after phase separation with Triton X-114. Autoradiography experiments performed with RB104, a new highly selective and potent NEP inhibitor, showed that NEP was expressed in both glomeruli and proximal tubules. The presence in glomeruli of NEP and some other brush-border peptidases (dipeptidyl-dipeptidase IV, aminopeptidase N and angiotensin I-converting enzyme) suggests that cell-surface peptidases might play an important role as regulators of plasma-derived peptides in this part of the nephron.

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A homologue of Drosophila tissue polarity gene frizzled is expressed in migrating myofibroblasts in the infarcted rat heart

Nature Medicine ◽

10.1038/nm0597-541 ◽

1997 ◽

Vol 3 (5) ◽

pp. 541-544 ◽

Cited By ~ 72

Author(s):

W. Matthijs Blankesteijn ◽

Yvonne P.G. Essers-Janssen ◽

Monique J.A. Verluyten ◽

Mat J.A.P. Daemen ◽

Jos F.M. Smits

Keyword(s):

Rat Heart ◽

Tissue Polarity ◽

Polarity Gene

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Regulation of Rho protein binding to membranes by rhoGDI: inhibition of releasing activity by physiological ionic conditions

Biochemistry and Cell Biology ◽

10.1139/o99-004 ◽

1999 ◽

Vol 77 (1) ◽

pp. 59-69 ◽

Cited By ~ 7

Author(s):

Diane Bilodeau ◽

Sylvie Lamy ◽

Richard R Desrosiers ◽

Denis Gingras ◽

Richard Béliveau

Keyword(s):

Ionic Strength ◽

Brush Border ◽

Rat Kidney ◽

Regulatory Protein ◽

Rho Proteins ◽

Glutathione S Transferase ◽

Free System ◽

Brush Border Membranes ◽

A Cell ◽

Membrane Bound

The Rho GDP dissociation inhibitor (GDI) is an ubiquitously expressed regulatory protein involved in the cycling of Rho proteins between membrane-bound and soluble forms. Here, we characterized the Rho solubilization activity of a glutathione S-transferase (GST) - GDI fusion protein in a cell-free system derived from rat kidney. Addition of GST-GDI to kidney brush border membranes resulted in the specific release of Cdc42 and RhoA from the membranes, while RhoB and Ras were not extracted. The release of Cdc42 and RhoA by GST-GDI was dose dependent and saturable with about 50% of both RhoA and Cdc42 extracted. The unextracted Rho proteins were tightly bound to membranes and could not be solubilized by repeated GST-GDI treatment. These results demonstrated that kidney brush border membranes contained two populations of RhoA and Cdc42. Furthermore, the GST-GDI solubilizing activity on membrane-bound Cdc42 and RhoA was abolished at physiological conditions of salt and temperature in all tissues examined. When using bead-immobilized GST-GDI, KCl did not reduced the binding of Rho proteins. However, washing brush border membranes with KCl prior treatment by GST-GDI inhibited the extraction of Rho proteins. Taken together, these results suggest that the binding of GDI to membrane-bound Cdc42 and RhoA occurs easily under physiological ionic strength conditions, but a complementary factor is required to extract these proteins from membranes. These observations suggest that the shuttling activity of GDI upon Rho proteins could be normally downregulated under physiological conditions.Key words: rhoGDI, rho proteins, ionic strength, kidney.

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