An allometric interpretation of the spatio-temporal organization of molecular and cellular processes

1993 ◽  
Vol 120 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Miguel Antonio Aon ◽  
Sonia Cortassa
Keyword(s):  
Temporal Organization ◽  
Cellular Processes ◽  
Spatio Temporal

E3 ubiquitin ligases

2005 ◽  
Vol 41 ◽  
pp. 15-30 ◽  
Author(s):  
Helen C. Ardley ◽  
Philip A. Robinson
Keyword(s):  
Protein Complexes ◽  
Loss Of Function ◽  
Direct Role ◽  
Cellular Processes ◽  
Substrate Protein ◽  
Protein Ubiquitination ◽  
C Terminus ◽  
Full Complement ◽  
Spatio Temporal ◽  
Eukaryotic Organisms

The selectivity of the ubiquitin–26 S proteasome system (UPS) for a particular substrate protein relies on the interaction between a ubiquitin-conjugating enzyme (E2, of which a cell contains relatively few) and a ubiquitin–protein ligase (E3, of which there are possibly hundreds). Post-translational modifications of the protein substrate, such as phosphorylation or hydroxylation, are often required prior to its selection. In this way, the precise spatio-temporal targeting and degradation of a given substrate can be achieved. The E3s are a large, diverse group of proteins, characterized by one of several defining motifs. These include a HECT (homologous to E6-associated protein C-terminus), RING (really interesting new gene) or U-box (a modified RING motif without the full complement of Zn2+-binding ligands) domain. Whereas HECT E3s have a direct role in catalysis during ubiquitination, RING and U-box E3s facilitate protein ubiquitination. These latter two E3 types act as adaptor-like molecules. They bring an E2 and a substrate into sufficiently close proximity to promote the substrate's ubiquitination. Although many RING-type E3s, such as MDM2 (murine double minute clone 2 oncoprotein) and c-Cbl, can apparently act alone, others are found as components of much larger multi-protein complexes, such as the anaphase-promoting complex. Taken together, these multifaceted properties and interactions enable E3s to provide a powerful, and specific, mechanism for protein clearance within all cells of eukaryotic organisms. The importance of E3s is highlighted by the number of normal cellular processes they regulate, and the number of diseases associated with their loss of function or inappropriate targeting.

scholarly journals The spatio-temporal organization of mitochondrial F1FO ATP synthase in cristae depends on its activity mode

2020 ◽  
Vol 1861 (1) ◽  
pp. 148091 ◽  
Author(s):  
Kirill Salewskij ◽  
Bettina Rieger ◽  
Frances Hager ◽  
Tasnim Arroum ◽  
Patrick Duwe ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Temporal Organization ◽  
F1fo Atp Synthase ◽  
Activity Mode ◽  
Spatio Temporal

scholarly journals Discrete simulations of spatio-temporal dynamics of small water bodies under varied stream flow discharges

2005 ◽  
Vol 12 (1) ◽  
pp. 31-40 ◽  
Author(s):  
B. S. Daya Sagar
Keyword(s):  
Water Body ◽  
Stream Flow ◽  
Fractal Dimensions ◽  
Temporal Patterns ◽  
Temporal Organization ◽  
Water Bodies ◽  
Flow Discharge ◽  
Small Water ◽  
Spatio Temporal ◽  
Small Water Bodies

Abstract. Spatio-temporal patterns of small water bodies (SWBs) under the influence of temporally varied stream flow discharge are simulated in discrete space by employing geomorphologically realistic expansion and contraction transformations. Cascades of expansion-contraction are systematically performed by synchronizing them with stream flow discharge simulated via the logistic map. Templates with definite characteristic information are defined from stream flow discharge pattern as the basis to model the spatio-temporal organization of randomly situated surface water bodies of various sizes and shapes. These spatio-temporal patterns under varied parameters (λs) controlling stream flow discharge patterns are characterized by estimating their fractal dimensions. At various λs, nonlinear control parameters, we show the union of boundaries of water bodies that traverse the water body and non-water body spaces as geomorphic attractors. The computed fractal dimensions of these attractors are 1.58, 1.53, 1.78, 1.76, 1.84, and 1.90, respectively, at λs of 1, 2, 3, 3.46, 3.57, and 3.99. These values are in line with general visual observations.

Spatio-Temporal Organization of the Mitochondrial Phase of Apoptosis

IUBMB Life ◽  
2001 ◽  
Vol 52 (3-5) ◽  
pp. 237-245 ◽  
Author(s):  
György Hajnóczky ◽  
Pál Pacher ◽  
Xuena Lin
Keyword(s):  
Temporal Organization ◽  
Spatio Temporal

scholarly journals Cross-linker–mediated regulation of actin network organization controls tissue morphogenesis

2019 ◽  
Vol 218 (8) ◽  
pp. 2743-2761 ◽  
Author(s):  
Daniel Krueger ◽  
Theresa Quinkler ◽  
Simon Arnold Mortensen ◽  
Carsten Sachse ◽  
Stefano De Renzis
Keyword(s):  
Myosin Ii ◽  
Temporal Organization ◽  
Tissue Morphogenesis ◽  
Animal Development ◽  
Spatio Temporal ◽  
Development In Vitro ◽  
Short Time ◽  
Actomyosin Contraction

Contraction of cortical actomyosin networks driven by myosin activation controls cell shape changes and tissue morphogenesis during animal development. In vitro studies suggest that contractility also depends on the geometrical organization of actin filaments. Here we analyze the function of actomyosin network topology in vivo using optogenetic stimulation of myosin-II in Drosophila embryos. We show that early during cellularization, hexagonally arrayed actomyosin fibers are resilient to myosin-II activation. Actomyosin fibers then acquire a ring-like conformation and become contractile and sensitive to myosin-II. This transition is controlled by Bottleneck, a Drosophila unique protein expressed for only a short time during early cellularization, which we show regulates actin bundling. In addition, it requires two opposing actin cross-linkers, Filamin and Fimbrin. Filamin acts synergistically with Bottleneck to facilitate hexagonal patterning, while Fimbrin controls remodeling of the hexagonal network into contractile rings. Thus, actin cross-linking regulates the spatio-temporal organization of actomyosin contraction in vivo, which is critical for tissue morphogenesis.

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