scholarly journals Spatial effects − site-specific regulation of actin and microtubule organization by septin GTPases

2018 ◽  
Vol 131 (1) ◽  
pp. jcs207555 ◽  
Author(s):  
Elias T. Spiliotis
Keyword(s):  
Spatial Effects ◽  
Microtubule Organization ◽  
Site Specific ◽  
Specific Regulation ◽  
Septin Gtpases

Site-specific regulation of organic osmolytes along the rat nephron

1996 ◽  
Vol 271 (3) ◽  
pp. F645-F652 ◽  
Author(s):  
M. Schmolke ◽  
A. Bornemann ◽  
W. G. Guder
Keyword(s):  
Urinary Bladder ◽  
High Performance ◽  
Lithium Treatment ◽  
Basolateral Membrane ◽  
Organic Osmolytes ◽  
Bladder Epithelium ◽  
Site Specific ◽  
Urinary Osmolality ◽  
Specific Regulation ◽  
Microdissected Tubules

The regulation of organic osmolytes was investigated in acute furosemide and chronic lithium diuresis along the nephron and in urinary bladder of rats. Sorbitol, myo-inositol, glycerophosphorylcholine, and betaine were measured enzymatically or by high performance liquid chromatography in homogenates and bioluminometrically in microdissected tubules. In untreated rats, all osmolytes except myo-inositol increased along the corticopapillary axis. An efflux of all osmolytes (-50%) was observed in homogenates of outer and inner medulla after acute furosemide diuresis (15 min, urinary osmolality = 329 mosmol/kgH2O) and for both polyols in microdissected tubules (30 min). In urinary bladder, only low concentrations of myo-inositol were found not to be affected by furosemide treatment. Chronic lithium treatment (7 days; urinary osmolality = 385 mosmol/kgH2O) decreased inner medullary but not outer medullary osmolyte concentrations. The results confirm a site-specific organic osmolyte pattern along the rat nephron, which is rapidly changed in a segment-specific way by different mechanisms of diuresis. The bladder epithelium does not accumulate organic osmolytes because no "osmotic gap" exists across the basolateral membrane. The osmotic difference across the apical membrane is maintained by the apical tightness of these cells.

Site-specific regulation of osteogenesis: Maintenance of discrete levels of phenotypic expression in vitro

1989 ◽  
Vol 223 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Christopher A. G. McCulloch ◽  
Howard C. Tenenbaum ◽  
Catherine A. Fair ◽  
Catalena Birek
Keyword(s):  
Phenotypic Expression ◽  
Site Specific ◽  
Specific Regulation

Site-specific regulation of CAV2.2 channels by protein kinase C isozymes βII and ε

Neuroscience ◽  
2009 ◽  
Vol 159 (2) ◽  
pp. 618-628 ◽  
Author(s):  
S. Rajagopal ◽  
H. Fang ◽  
C.I.A. Oronce ◽  
S. Jhaveri ◽  
S. Taneja ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Site Specific ◽  
Kinase C ◽  
Specific Regulation

scholarly journals Laser Microdissection of Grapevine Leaves Reveals Site-Specific Regulation of Transcriptional Response toPlasmopara viticola

2015 ◽  
Vol 57 (1) ◽  
pp. 69-81 ◽  
Author(s):  
Luisa Lenzi ◽  
Carla Caruso ◽  
Pier Luigi Bianchedi ◽  
Ilaria Pertot ◽  
Michele Perazzolli
Keyword(s):  
Laser Microdissection ◽  
Transcriptional Response ◽  
Site Specific ◽  
Grapevine Leaves ◽  
Specific Regulation

scholarly journals Analytical reduction of combinatorial complexity arising from multiple protein modification sites

2015 ◽  
Vol 12 (103) ◽  
pp. 20141215 ◽  
Author(s):  
Marc R. Birtwistle
Keyword(s):  
Protein Modification ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Adaptor Proteins ◽  
System Size ◽  
Combinatorial Complexity ◽  
Biochemical Networks ◽  
Local Concentration ◽  
Site Specific ◽  
Specific Regulation

Combinatorial complexity is a major obstacle to ordinary differential equation (ODE) modelling of biochemical networks. For example, a protein with 10 sites that can each be unphosphorylated, phosphorylated or bound to adaptor protein requires 3 10 ODEs. This problem is often dealt with by making ad hoc assumptions which have unclear validity and disallow modelling of site-specific dynamics. Such site-specific dynamics, however, are important in many biological systems. We show here that for a common biological situation where adaptors bind modified sites, binding is slow relative to modification/demodification, and binding to one modified site hinders binding to other sites, for a protein with n modification sites and m adaptor proteins the number of ODEs needed to simulate the site-specific dynamics of biologically relevant, lumped bound adaptor states is independent of the number of modification sites and equal to m + 1, giving a significant reduction in system size. These considerations can be relaxed considerably while retaining reasonably accurate descriptions of the true system dynamics. We apply the theory to model, using only 11 ODEs, the dynamics of ligand-induced phosphorylation of nine tyrosines on epidermal growth factor receptor (EGFR) and primary recruitment of six signalling proteins (Grb2, PI3K, PLCγ1, SHP2, RasA1 and Shc1). The model quantitatively accounts for experimentally determined site-specific phosphorylation and dephosphorylation rates, differential affinities of binding proteins for the phosphorylated sites and binding protein expression levels. Analysis suggests that local concentration of site-specific phosphatases such as SHP2 in membrane subdomains by a factor of approximately 10 7 is critical for effective site-specific regulation. We further show how our framework can be extended with minimal effort to consider binding cooperativity between Grb2 and c-Cbl, which is important for receptor trafficking. Our theory has potentially broad application to reduce combinatorial complexity and allow practical simulation of a variety ODE models relevant to systems biology and pharmacology applications to allow exploration of key aspects of complexity that control signal flux.

Sign in / Sign up

Export Citation Format

Share Document