scholarly journals The function of the Drosophila fat facets deubiquitinating enzyme in limiting photoreceptor cell number is intimately associated with endocytosis

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1727-1736 ◽  
Author(s):  
A.L. Cadavid ◽  
A. Ginzel ◽  
J.A. Fischer
Keyword(s):  
Compound Eye ◽  
Cell Communication ◽  
Photoreceptor Cells ◽  
Cell Number ◽  
Deubiquitinating Enzyme ◽  
A Cell ◽  
Fat Facets ◽  
Liquid Facets ◽  
And Function ◽  
Communication Pathway

Fat facets is a deubiquitinating enzyme required in a cell communication pathway that limits to eight the number of photoreceptor cells in each facet of the Drososphila compound eye. Genetic data support a model whereby Faf removes ubiquitin, a polypeptide tag for protein degradation, from a specific ubiquitinated protein thus preventing its degradation. Here, mutations in the liquid facets gene were identified as dominant enhancers of the fat facets mutant eye phenotype. The liquid facets locus encodes epsin, a vertebrate protein associated with the clathrin endocytosis complex. The results of genetic experiments reveal that fat facets and liquid facets facilitate endocytosis and function in common cells to generate an inhibitory signal that prevents ectopic photoreceptor determination. Moreover, it is demonstrated that the fat facets mutant phenotype is extraordinarily sensitive to the level of liquid facets expression. We propose that Liquid facets is a candidate for the critical substrate of Fat facets in the eye.

scholarly journals Genetic Analysis of the DrosophilaDNAprimGene: The Function of the 60-kD Primase Subunit of DNA Polymerase Opposes thefat facetsSignaling Pathway in the Developing Eye

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1787-1795 ◽  
Author(s):  
Xin Chen ◽  
Qinghong Li ◽  
Janice A Fischer
Keyword(s):  
Dna Polymerase ◽  
Dna Sequences ◽  
Compound Eye ◽  
Large Subunit ◽  
Cell Communication ◽  
Dna Primase ◽  
Morphological Defects ◽  
Dependent Cell ◽  
Fat Facets ◽  
Communication Pathway

AbstractThe Drosophila DNAprim gene encodes the large subunit (60 kD) of DNA primase, the part of DNA polymerase α that synthesizes RNA primers during DNA replication. The precise function of the 60-kD subunit is unknown. In a mutagenesis screen for suppressors of the fat facets (faf) mutant eye phenotype, we identified mutations in DNAprim. The faf gene encodes a deubiquitinating enzyme required specifically for patterning the compound eye. The DNA sequences of four DNAprim alleles were determined and these define essential protein domains. We show that while flies lacking DNAprim activity are lethal, flies with reduced DNAprim activity display morphological defects in their eyes, and unlike faf mutants, cell cycle abnormalities in larval eye discs. Mechanisms by which DNA primase levels might influence the faf-dependent cell communication pathway are discussed.

Establishment of a cell-to-cell communication pathway between separate carpels during gynoecium development

Planta ◽  
1995 ◽  
Vol 195 (3) ◽  
pp. 450-455 ◽  
Author(s):  
Chris van der Schoot ◽  
Margaret A. Dietrich ◽  
Marc Storms ◽  
Judith A. Verbeke ◽  
William J. Lucas
Keyword(s):  
Cell Communication ◽  
A Cell ◽  
Communication Pathway ◽  
Gynoecium Development

scholarly journals Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

2018 ◽  
Vol 14 ◽  
pp. 1769-1777 ◽  
Author(s):  
Bimal Koirala ◽  
Robert A Hillman ◽  
Erin K Tiwold ◽  
Michael A Bertucci ◽  
Yftah Tal-Gan
Keyword(s):  
Streptococcus Pneumoniae ◽  
Hydrophobic Interactions ◽  
Point Mutations ◽  
Cell Communication ◽  
Cell Number ◽  
Chronic Infections ◽  
Drug Candidates ◽  
A Cell ◽  
Natural Amino Acids ◽  
Protease Degradation

Quorum sensing (QS) is a cell–cell communication mechanism that enables bacteria to assess their population density and alter their behavior upon reaching high cell number. Many bacterial pathogens utilize QS to initiate an attack on their host, thus QS has attracted significant attention as a potential antivirulence alternative to traditional antibiotics. Streptococcus pneumoniae, a notorious human pathogen responsible for a variety of acute and chronic infections, utilizes the competence regulon and its associated signaling peptide, the competence stimulating peptide (CSP), to acquire antibiotic resistance and establish an infection. In this work, we sought to define the binding pockets within the ComD1 receptor used for binding the hydrophobic side-chain residues in CSP1 through the introduction of highly-conservative point mutations within the peptide. Optimization of these binding interactions could lead to the development of highly potent CSP-based QS modulators while the inclusion of non-natural amino acids within the CSP sequence would confer resistance to protease degradation, a requirement for drug candidates.

scholarly journals In Vivo Structure/Function Analysis of the Drosophila fat facets Deubiquitinating Enzyme Gene

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1829-1836 ◽  
Author(s):  
Xin Chen ◽  
Janice A Fischer
Keyword(s):  
Amino Acid ◽  
Dna Sequences ◽  
Compound Eye ◽  
Function Analysis ◽  
P Element ◽  
Amino Acid Sequence Similarity ◽  
Deubiquitinating Enzyme ◽  
Specific Substrate ◽  
Deubiquitinating Enzymes ◽  
Fat Facets

Abstract The Drosophila Fat facets protein is a deubiquitinating enzyme required for patterning the developing compound eye. Ubiquitin, a 76-amino-acid polypeptide, serves as a tag to direct proteins to the proteasome, a protein degradation complex. Deubiquitinating enzymes are a large group of proteins that cleave ubiquitin-protein bonds. Fat facets belongs to a class of deubiquitinating enzymes called Ubps that share a conserved catalytic domain. Fat facets is unique among them in its large size and also because Fat facets is thought to deubiquitinate a specific substrate thereby preventing its proteolysis. Here we asked which portions of the Fat facets protein are essential for its function. P-element constructs that express partial Fat facets proteins were tested for function. In addition, the DNA sequences of 12 mutant fat facets alleles were determined. Finally, regions of amino acid sequence similarity in 18 Drosophila Ubps revealed by the Genome Project were identified. The results indicate functions for specific conserved amino acids in the catalytic region of Fat facets and also indicate that regions of the protein both N- and C-terminal to the catalytic region are required for Fat facets function.

Dynamics of Drosophila eye development and temporal requirements of sevenless expression

Development ◽  
1989 ◽  
Vol 107 (4) ◽  
pp. 723-731 ◽  
Author(s):  
K. Basler ◽  
E. Hafen
Keyword(s):  
Imaginal Disc ◽  
Compound Eye ◽  
Eye Development ◽  
Photoreceptor Cells ◽  
Anterior Border ◽  
Conditional Allele ◽  
And Function ◽  
Internal Marker ◽  
Eye Imaginal Disc

The development of the compound eye of Drosophila consists of a linear, stereotyped program starting at the posterior end of the eye imaginal disc and progressing towards the anterior border. The determination of the R7 photoreceptor cells is part of this process and is dependent on the sevenless gene. In this study, we used a heat-shock-inducible sevenless gene as a conditional allele to determine the exact temporal requirements of sevenless gene expression and to reveal the stages of ommatidial development during which the presumptive R7 cell can respond to the presence of sevenless protein. Our results indicate that sevenless gene function is only required during a brief, defined period for the initiation of R7 development; subsequently sevenless is dispensable for both differentiation and function of the R7 photoreceptors. Furthermore, using rescue of R7 cells as an internal marker to monitor the progression of eye development we could examine when and at what rate ommatidial columns form.

Actin and α-tubulin immuno-EM labelings reveal differences in intra versus interphotoreceptor matrix

1990 ◽  
Vol 48 (3) ◽  
pp. 466-467
Author(s):  
Matti Järvilehto ◽  
Riitta Harjula
Keyword(s):  
Compound Eye ◽  
Frozen Section ◽  
Smooth Muscle Actin ◽  
Photoreceptor Cells ◽  
Immune Serum ◽  
Cell Organelles ◽  
Calliphora Erythrocephala ◽  
Optical Axes ◽  
Interphotoreceptor Matrix ◽  
Similar Kind

The photoreceptor cells in the compound eyes of higher diptera are clustered in groups (ommatidia) of eight receptor cells. The cells from six adjacent ommatidia are organized into optical units, neuro-ommatia sharing the same visual field. In those ommatidia the optical axes of the photopigment containing structures (rhabdomeres) are parallel. The rhabdomeres of the photoreceptor cells are separated from each other by an interstitial i.e innerommatidial space (IOS). In the photoreceptor cell body, besides of the normal cell organelles, a cellular matrix is a structurally apparent component. Similar kind of reticular formation is also found in the IOS containing some unidentified filamentary substance, of which composition and functional significance for optical properties of vision is the aim of this report.The prefixed (2% PA + 0.2% GA in 0.1-n phosphate buffer, pH 7.4, for 1h), frozen section blocks of the compound eye of the blowfly (Calliphora erythrocephala) were prepared by immuno-cryo-techniques. The ultrathin cryosections were incubated with antibodies of monoclonal α-tubulin and polyclonal smooth muscle actin. Control labelings of excess of antigen, non-immune serum and non-present antibody were perforated.

CD38 as an immunomodulator in cancer

2020 ◽  
Vol 16 (34) ◽  
pp. 2853-2861
Author(s):  
Yanli Li ◽  
Rui Yang ◽  
Limo Chen ◽  
Sufang Wu
Keyword(s):  
Multiple Myeloma ◽  
Cell Activation ◽  
Human Tissues ◽  
Transmembrane Glycoprotein ◽  
Cell Activation Marker ◽  
Research Findings ◽  
A Cell ◽  
And Function ◽  
Human Molecule

CD38 is a transmembrane glycoprotein that is widely expressed in a variety of human tissues and cells, especially those in the immune system. CD38 protein was previously considered as a cell activation marker, and today monoclonal antibodies targeting CD38 have witnessed great achievements in multiple myeloma and promoted researchers to conduct research on other tumors. In this review, we provide a wide-ranging review of the biology and function of the human molecule outside the field of myeloma. We focus mainly on current research findings to summarize and update the findings gathered from diverse areas of study. Based on these findings, we attempt to extend the role of CD38 in the context of therapy of solid tumors and expand the role of the molecule from a simple marker to an immunomodulator.

scholarly journals Maturation of the Na,K-ATPase in the Endoplasmic Reticulum in Health and Disease

2021 ◽  
Author(s):  
Vitalii Kryvenko ◽  
Olga Vagin ◽  
Laura A. Dada ◽  
Jacob I. Sznajder ◽  
István Vadász
Keyword(s):  
Endoplasmic Reticulum ◽  
Intracellular Signaling ◽  
Loss Of Function ◽  
Α Subunit ◽  
Rate Limiting Step ◽  
Atpase Subunits ◽  
A Cell ◽  
Health And Disease ◽  
And Function ◽  
Rate Limiting

Abstract The Na,K-ATPase establishes the electrochemical gradient of cells by driving an active exchange of Na+ and K+ ions while consuming ATP. The minimal functional transporter consists of a catalytic α-subunit and a β-subunit with chaperon activity. The Na,K-ATPase also functions as a cell adhesion molecule and participates in various intracellular signaling pathways. The maturation and trafficking of the Na,K-ATPase include co- and post-translational processing of the enzyme in the endoplasmic reticulum (ER) and the Golgi apparatus and subsequent delivery to the plasma membrane (PM). The ER folding of the enzyme is considered as the rate-limiting step in the membrane delivery of the protein. It has been demonstrated that only assembled Na,K-ATPase α:β-complexes may exit the organelle, whereas unassembled, misfolded or unfolded subunits are retained in the ER and are subsequently degraded. Loss of function of the Na,K-ATPase has been associated with lung, heart, kidney and neurological disorders. Recently, it has been shown that ER dysfunction, in particular, alterations in the homeostasis of the organelle, as well as impaired ER-resident chaperone activity may impede folding of Na,K-ATPase subunits, thus decreasing the abundance and function of the enzyme at the PM. Here, we summarize our current understanding on maturation and subsequent processing of the Na,K-ATPase in the ER under physiological and pathophysiological conditions. Graphic Abstract

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