scholarly journals Quantitative analysis of autophagy-related protein stoichiometry by fluorescence microscopy

2008 ◽  
Vol 182 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Jiefei Geng ◽  
Misuzu Baba ◽  
Usha Nair ◽  
Daniel J. Klionsky
Keyword(s):  
Quantitative Analysis ◽  
Fluorescence Microscopy ◽  
Periodic Change ◽  
Related Protein ◽  
Atg Proteins ◽  
Autophagy Induction ◽  
Phagophore Assembly Site ◽  
Insight Into ◽  
Assembly Site

In yeast, ∼31 autophagy-related (Atg) proteins have been identified. Most of them reside at the phagophore assembly site (PAS), although the function of the PAS mostly remains unclear. One reason for the latter is the lack of stoichiometric information regarding the Atg proteins at this site. We report the application of fluorescence microscopy to study the amount of Atg proteins at the PAS. We find that an increase in the amount of Atg11 at the PAS enhances the recruitment of Atg8 and Atg9 to this site and facilitates the formation of more cytoplasm-to-vacuole targeting vesicles. In response to autophagy induction, the amount of most Atg proteins remains unchanged at the PAS, whereas we see an enhanced recruitment of Atg8 and 9 at this site. During autophagy, the amount of Atg8 at the PAS showed a periodic change, indicating the formation of autophagosomes. Application of this method and further analysis will provide more insight into the functions of Atg proteins.

scholarly journals Post-Golgi Sec Proteins Are Required for Autophagy in Saccharomyces cerevisiae

2010 ◽  
Vol 21 (13) ◽  
pp. 2257-2269 ◽  
Author(s):  
Jiefei Geng ◽  
Usha Nair ◽  
Kyoko Yasumura-Yorimitsu ◽  
Daniel J. Klionsky
Keyword(s):  
Nucleotide Exchange ◽  
Membrane Flow ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Conditional Mutant ◽  
Autophagy Induction ◽  
Atg Genes ◽  
Response To Environmental Change ◽  
Insight Into ◽  
Assembly Site

In eukaryotic cells, autophagy mediates the degradation of cytosolic contents in response to environmental change. Genetic analyses in fungi have identified over 30 autophagy-related (ATG) genes and provide substantial insight into the molecular mechanism of this process. However, one essential issue that has not been resolved is the origin of the lipids that form the autophagosome, the sequestering vesicle that is critical for autophagy. Here, we report that two post-Golgi proteins, Sec2 and Sec4, are required for autophagy. Sec4 is a Rab family GTPase, and Sec2 is its guanine nucleotide exchange factor. In sec2 and sec4 conditional mutant yeast, the anterograde movement of Atg9, a proposed membrane carrier, is impaired during starvation conditions. Similarly, in the sec2 mutant, Atg8 is inefficiently recruited to the phagophore assembly site, which is involved in autophagosome biogenesis, resulting in the generation of fewer autophagosomes. We propose that following autophagy induction the function of Sec2 and Sec4 are diverted to direct membrane flow to autophagosome formation.

scholarly journals Quantitative analysis of autophagy-related protein stoichiometry by fluorescence microscopy

2008 ◽  
Vol 183 (6) ◽  
pp. 1175-1175 ◽  
Author(s):  
Jiefei Geng ◽  
Misuzu Baba ◽  
Usha Nair ◽  
Daniel J. Klionsky
Keyword(s):  
Quantitative Analysis ◽  
Fluorescence Microscopy ◽  
Related Protein

Quantitative Analysis Of X-Ray Images From Geological Materials

1990 ◽  
Vol 48 (2) ◽  
pp. 244-245
Author(s):  
J. M. Paque ◽  
R. Browning ◽  
P. L. King ◽  
P. Pianetta
Keyword(s):  
Quantitative Analysis ◽  
Bulk Composition ◽  
Principal Component ◽  
Analytical Description ◽  
Bulk Sample ◽  
Geological Samples ◽  
X Ray ◽  
Software And Hardware ◽  
And Storage ◽  
Insight Into

Geological samples typically contain many minerals (phases) with multiple element compositions. A complete analytical description should give the number of phases present, the volume occupied by each phase in the bulk sample, the average and range of composition of each phase, and the bulk composition of the sample. A practical approach to providing such a complete description is from quantitative analysis of multi-elemental x-ray images.With the advances in recent years in the speed and storage capabilities of laboratory computers, large quantities of data can be efficiently manipulated. Commercial software and hardware presently available allow simultaneous collection of multiple x-ray images from a sample (up to 16 for the Kevex Delta system). Thus, high resolution x-ray images of the majority of the detectable elements in a sample can be collected. The use of statistical techniques, including principal component analysis (PCA), can provide insight into mineral phase composition and the distribution of minerals within a sample.

New insight into the molecular switch mechanism of human Rho family proteins: shifting a paradigm

2013 ◽  
Vol 394 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Mamta Jaiswal ◽  
Eyad Kalawy Fansa ◽  
Radovan Dvorsky ◽  
Mohammad Reza Ahmadian
Keyword(s):  
Quantitative Analysis ◽  
Bound State ◽  
Molecular Switch ◽  
Nucleotide Exchange ◽  
Gtp Binding ◽  
Switch Mechanism ◽  
Rho Family ◽  
Rho Family Proteins ◽  
Insight Into ◽  
Made In

Abstract Major advances have been made in understanding the structure, function and regulation of the small GTP-binding proteins of the Rho family and their involvement in multiple cellular process and disorders. However, intrinsic nucleotide exchange and hydrolysis reactions, which are known to be fundamental to Rho family proteins, have been partially investigated in the case of RhoA, Rac1 and Cdc42, but for others not at all. Here we present a comprehensive and quantitative analysis of the molecular switch functions of 15 members of the Rho family that enabled us to propose an active GTP-bound state for the rather uncharacterized isoforms RhoD and Rif under equilibrium and quiescent conditions.

Mapping of ligand binding sites provides insight into the function of factor H-related protein 5

2017 ◽  
Vol 89 ◽  
pp. 145
Author(s):  
Alexandra Papp ◽  
Marcell Cserhalmi ◽  
Ádám I. Csincsi ◽  
Barbara Uzonyi ◽  
David Ermert ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Binding Sites ◽  
Factor H ◽  
Related Protein ◽  
Ligand Binding Sites ◽  
Insight Into
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