Control of Cell Fate by a Deubiquitinating Enzyme Encoded by the fat facets Gene

Science ◽  
1995 ◽  
Vol 270 (5243) ◽  
pp. 1828-1831 ◽  
Author(s):  
Y. Huang ◽  
R. T. Baker ◽  
J. A. Fischer-Vize
Keyword(s):  
Cell Fate ◽  
Deubiquitinating Enzyme ◽  
Fat Facets

scholarly journals The Ras Target AF-6 is a Substrate of the Fam Deubiquitinating Enzyme

1998 ◽  
Vol 142 (4) ◽  
pp. 1053-1062 ◽  
Author(s):  
Shinichiro Taya ◽  
Takaharu Yamamoto ◽  
Kyoko Kano ◽  
Yoji Kawano ◽  
Akihiro Iwamatsu ◽  
...  
Keyword(s):  
Cell Fate ◽  
Plasma Membranes ◽  
Critical Role ◽  
Amino Acid Sequences ◽  
Cell Contact ◽  
Deubiquitinating Enzyme ◽  
Intact Cells ◽  
Cell Adhesions ◽  
Fat Facets ◽  
Cell Cell

The Ras target AF-6 has been shown to serve as one of the peripheral components of cell–cell adhesions, and is thought to participate in cell–cell adhesion regulation downstream of Ras. We here purified an AF-6-interacting protein with a molecular mass of ∼220 kD (p220) to investigate the function of AF-6 at cell–cell adhesions. The peptide sequences of p220 were identical to the amino acid sequences of mouse Fam. Fam is homologous to a deubiquitinating enzyme in Drosophila, the product of the fat facets gene. Recent genetic analyses indicate that the deubiquitinating activity of the fat facets product plays a critical role in controlling the cell fate. We found that Fam accumulated at the cell–cell contact sites of MDCKII cells, but not at free ends of plasma membranes. Fam was partially colocalized with AF-6 and interacted with AF-6 in vivo and in vitro. We also showed that AF-6 was ubiquitinated in intact cells, and that Fam prevented the ubiquitination of AF-6.

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.

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.

On the conservation of function of the Drosophila Fat facets deubiquitinating enzyme and Fam, its mouse homolog

2000 ◽  
Vol 210 (12) ◽  
pp. 603-610 ◽  
Author(s):  
X. Chen ◽  
Erin Overstreet ◽  
Stephen A. Wood ◽  
J. A. Fischer
Keyword(s):  
Deubiquitinating Enzyme ◽  
Mouse Homolog ◽  
Fat Facets

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

Centromere assembly and non-random sister chromatid segregation in stem cells

2020 ◽  
Vol 64 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Ben L. Carty ◽  
Elaine M. Dunleavy
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Cell Fate ◽  
Sister Chromatid ◽  
Asymmetric Cell Division ◽  
Protein A ◽  
Germline Stem Cells ◽  
Sister Chromatids ◽  
Centromere Protein A ◽  
Oocyte Meiosis

Abstract Asymmetric cell division (ACD) produces daughter cells with separate distinct cell fates and is critical for the development and regulation of multicellular organisms. Epigenetic mechanisms are key players in cell fate determination. Centromeres, epigenetically specified loci defined by the presence of the histone H3-variant, centromere protein A (CENP-A), are essential for chromosome segregation at cell division. ACDs in stem cells and in oocyte meiosis have been proposed to be reliant on centromere integrity for the regulation of the non-random segregation of chromosomes. It has recently been shown that CENP-A is asymmetrically distributed between the centromeres of sister chromatids in male and female Drosophila germline stem cells (GSCs), with more CENP-A on sister chromatids to be segregated to the GSC. This imbalance in centromere strength correlates with the temporal and asymmetric assembly of the mitotic spindle and potentially orientates the cell to allow for biased sister chromatid retention in stem cells. In this essay, we discuss the recent evidence for asymmetric sister centromeres in stem cells. Thereafter, we discuss mechanistic avenues to establish this sister centromere asymmetry and how it ultimately might influence cell fate.

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