Mosaic Mutant Analysis Identifies PDGFRα/PDGFRβ as Negative Regulators of Adipogenesis

AbstractEndocytosis mediates the cellular uptake of micronutrients and cell surface proteins. Fast Endophilin-mediated endocytosis, FEME, is not constitutively active but triggered upon receptor activation. High levels of growth factors induce spontaneous FEME, which can be suppressed upon serum starvation. This suggested a role for protein kinases in this growth factor receptor-mediated regulation. Using chemical and genetic inhibition, we find that Cdk5 and GSK3β are negative regulators of FEME. They antagonize the binding of Endophilin to Dynamin-1 and to CRMP4, a Plexin A1 adaptor. This control is required for proper axon elongation, branching and growth cone formation in hippocampal neurons. The kinases also block the recruitment of Dynein onto FEME carriers by Bin1. As GSK3β binds to Endophilin, it imposes a local regulation of FEME. Thus, Cdk5 and GSK3β are key regulators of FEME, licensing cells for rapid uptake by the pathway only when their activity is low.

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Regulation of Bacillus subtilis aprE Expression by glnA through Inhibition of scoC and σD-Dependent degR Expression

Journal of Bacteriology ◽

10.1128/jb.00049-09 ◽

2009 ◽

Vol 191 (9) ◽

pp. 3050-3058 ◽

Cited By ~ 12

Author(s):

Sadanobu Abe ◽

Ayako Yasumura ◽

Teruo Tanaka

Keyword(s):

Bacillus Subtilis ◽

Glutamine Synthetase ◽

Alkaline Protease ◽

Negative Regulator ◽

Negative Regulators ◽

Global Regulation ◽

Positive Regulation ◽

Expression Levels ◽

Negative Effect ◽

Positive Effect

ABSTRACT Expression of the gene for the extracellular alkaline protease (aprE) of Bacillus subtilis is subject to regulation by many positive and negative regulators. We have found that aprE expression was increased by disruption of the glutamine synthetase gene glnA. The increase in aprE expression was attributed to a decreased in expression of scoC, which encodes a negative regulator of aprE expression. The glnA effect on scoC expression was abolished by further disruption of tnrA, indicating that aprE expression is under global regulation through TnrA. In the scoC background, however, aprE expression was decreased by glnA deletion, and it was shown that the decrease was due to a defect in positive regulation by DegU. Among the genes that affect aprE expression through DegU, the expression of degR, encoding a protein that stabilizes phosphorylated DegU, was inhibited by glnA deletion. It was further shown that the decrease in degR expression by glnA deletion was caused by inhibition of the expression of sigD, encoding the σD factor, which is required for degR expression. In accordance with these findings, the expression levels of aprE-lacZ in glnA scoC degR and scoC degR strains were identical. These results led us to conclude that glnA deletion brings about two effects on aprE expression, i.e., a positive effect through inhibition of scoC expression and a negative effect through inhibition of degR expression, with the former predominating over the latter.

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Diversity of Pod Shape in Pisum

Diversity ◽

10.3390/d13050203 ◽

2021 ◽

Vol 13 (5) ◽

pp. 203

Author(s):

Thomas Henry Noel Ellis ◽

Julie M. I. Hofer ◽

Eleni Vikeli ◽

Michael J. Ambrose ◽

Paola Higuera-Poveda ◽

...

Keyword(s):

Allelic Variation ◽

Size Variation ◽

Width Ratio ◽

Negative Regulators ◽

Wide Range ◽

Yield Determination ◽

Organ Specific ◽

Length Width ◽

End Use ◽

Pod Length

The seed-containing pod is the defining structure of plants in the legume family, yet pods exhibit a wide range of morphological variation. Within a species pod characters are likely to be correlated with reproductive strategy, and within cultivated forms will correspond to aspects of yield determination and/or end use. Here variation in pod size, described as pod length: pod width ratio, has been analyzed in pea germplasm represented by 597 accessions. This pod size variation is discussed with respect to population structure and to known classical pod morphology mutants. Variability of the pod length: width ratio can be explained by allelic variation at two genetic loci that may correspond to organ-specific negative regulators of growth.

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Enhancer of Polycomb Is a Suppressor of Position-Effect Variegation in Drosophila melanogaster

Genetics ◽

10.1093/genetics/148.1.211 ◽

1998 ◽

Vol 148 (1) ◽

pp. 211-220

Author(s):

Donald A R Sinclair ◽

Nigel J Clegg ◽

Jennifer Antonchuk ◽

Thomas A Milne ◽

Kryn Stankunas ◽

...

Keyword(s):

Sequence Similarity ◽

Position Effect ◽

Polycomb Group ◽

P Element ◽

Homeotic Gene ◽

Position Effect Variegation ◽

Negative Regulators ◽

Recombination Mapping ◽

Effect Variegation ◽

Homeotic Gene Expression

Abstract Polycomb group (PcG) genes of Drosophila are negative regulators of homeotic gene expression required for maintenance of determination. Sequence similarity between Polycomb and Su(var)205 led to the suggestion that PcG genes and modifiers of position-effect variegation (PEV) might function analogously in the establishment of chromatin structure. If PcG proteins participate directly in the same process that leads to PEV, PcG mutations should suppress PEV. We show that mutations in E(Pc), an unusual member of the PcG, suppress PEV of four variegating rearrangements: In(l)wm4, BSV, T(2;3)SbV, and In(2R)bwVDe2. Using reversion of a P element insertion, deficiency mapping, and recombination mapping as criteria, homeotic effects and suppression of PEV associated with E(Pc) co-map. Asx is an enhancer of PEV, whereas nine other PcG loci do not affect PEV. These results support the conclusion that there are fewer similarities between PcG genes and modifiers of PEV than previously supposed. However, E(Pc) appears to be an important link between the two groups. We discuss why Asx might act as an enhancer of PEV.

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