scholarly journals Role of STE genes in the mating factor signaling pathway mediated by GPA1 in Saccharomyces cerevisiae.

1988 ◽  
Vol 8 (9) ◽  
pp. 3777-3783 ◽  
Author(s):  
N Nakayama ◽  
Y Kaziro ◽  
K Arai ◽  
K Matsumoto
Keyword(s):  
Steady State ◽  
Signaling Pathway ◽  
State Level ◽  
G1 Arrest ◽  
Gene Products ◽  
Mating Efficiency ◽  
Protein Functions ◽  
Steady State Levels ◽  
Mating Factor

The ste mutants (ste2, ste4, ste5, ste7, ste11, and ste12) are insensitive to mating factors and are, therefore, sterile. Roles of the STE gene products in the GPA1-mediated mating factor signaling pathway were studied by using ste gpa1 double mutants. Mating efficiency of a ste2 mutant defective in the alpha-factor receptor increased 1,000-fold in a gpa1 background, while G1 arrest and aberrant morphology (shmoo) caused by gpa1 were not suppressed by ste2. Furthermore, the steady-state level of the FUS1 transcript, which normally increases in response to mating factors, was also elevated when the GPA1 function was impaired. These results suggest that the GPA1 protein functions downstream of the STE2 receptor. Conversely, the sterility of ste4, ste5, ste7, ste11, and ste12 mutants was not suppressed by gpa1, but the lethal phenotype of gpa1 was suppressed by these ste mutations. Northern (RNA) blotting analysis revealed that the ste7, ste11, and ste12 mutations caused reductions of 50 to 70% in the steady-state levels of the GPA1 transcript, while ste4 had a slight effect and ste5 had no effect. This implies that the suppression by ste7, ste11, and ste12 could be due to reduced syntheses of additional components, including an effector, and that suppression by ste4 and ste5 may result from direct effects on the signaling pathway. The STE4, STE5, STE7, STE11, and STE12 products, therefore, appear to specify components of the signal transduction machinery, directly or indirectly, which function together with or downstream of GPA1.

Role of STE genes in the mating factor signaling pathway mediated by GPA1 in Saccharomyces cerevisiae

1988 ◽  
Vol 8 (9) ◽  
pp. 3777-3783
Author(s):  
N Nakayama ◽  
Y Kaziro ◽  
K Arai ◽  
K Matsumoto
Keyword(s):  
Steady State ◽  
Signaling Pathway ◽  
State Level ◽  
G1 Arrest ◽  
Gene Products ◽  
Mating Efficiency ◽  
Protein Functions ◽  
Steady State Levels ◽  
Mating Factor

The ste mutants (ste2, ste4, ste5, ste7, ste11, and ste12) are insensitive to mating factors and are, therefore, sterile. Roles of the STE gene products in the GPA1-mediated mating factor signaling pathway were studied by using ste gpa1 double mutants. Mating efficiency of a ste2 mutant defective in the alpha-factor receptor increased 1,000-fold in a gpa1 background, while G1 arrest and aberrant morphology (shmoo) caused by gpa1 were not suppressed by ste2. Furthermore, the steady-state level of the FUS1 transcript, which normally increases in response to mating factors, was also elevated when the GPA1 function was impaired. These results suggest that the GPA1 protein functions downstream of the STE2 receptor. Conversely, the sterility of ste4, ste5, ste7, ste11, and ste12 mutants was not suppressed by gpa1, but the lethal phenotype of gpa1 was suppressed by these ste mutations. Northern (RNA) blotting analysis revealed that the ste7, ste11, and ste12 mutations caused reductions of 50 to 70% in the steady-state levels of the GPA1 transcript, while ste4 had a slight effect and ste5 had no effect. This implies that the suppression by ste7, ste11, and ste12 could be due to reduced syntheses of additional components, including an effector, and that suppression by ste4 and ste5 may result from direct effects on the signaling pathway. The STE4, STE5, STE7, STE11, and STE12 products, therefore, appear to specify components of the signal transduction machinery, directly or indirectly, which function together with or downstream of GPA1.

scholarly journals The critical role of T cells in glucocorticoid-induced osteoporosis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Lin Song ◽  
Lijuan Cao ◽  
Rui Liu ◽  
Hui Ma ◽  
Yanan Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
Side Effects ◽  
Critical Role ◽  
Wild Type ◽  
Receptor Activator ◽  
Steady State Levels ◽  
Induced Apoptosis

AbstractGlucocorticoids (GC) are widely used clinically, despite the presence of significant side effects, including glucocorticoid-induced osteoporosis (GIOP). While GC are believed to act directly on osteoblasts and osteoclasts to promote osteoporosis, the detailed underlying molecular mechanism of GC-induced osteoporosis is still not fully elucidated. Here, we show that lymphocytes play a pivotal role in regulating GC-induced osteoporosis. We show that GIOP could not be induced in SCID mice that lack T cells, but it could be re-established by adoptive transfer of splenic T cells from wild-type mice. As expected, T cells in the periphery are greatly reduced by GC; instead, they accumulate in the bone marrow where they are protected from GC-induced apoptosis. These bone marrow T cells in GC-treated mice express high steady-state levels of NF-κB receptor activator ligand (RANKL), which promotes the formation and maturation of osteoclasts and induces osteoporosis. Taken together, these findings reveal a critical role for T cells in GIOP.

Influence of erythrocyte aggregation on leukocyte margination in postcapillary venules of rat mesentery

2000 ◽  
Vol 279 (4) ◽  
pp. H1460-H1471 ◽  
Author(s):  
Mark J. Pearson ◽  
Herbert H. Lipowsky
Keyword(s):  
Steady State ◽  
Blood Cell ◽  
Aggregate Size ◽  
State Level ◽  
Erythrocyte Aggregation ◽  
Shear Rates ◽  
Rat Mesentery ◽  
Rbc Aggregation ◽  
Proximal Occlusion

The role of erythrocyte (red blood cell; RBC) aggregation in affecting leukocyte (white blood cell; WBC) margination in postcapillary venules of the mesentery (rat) was explored by direct intravital microscopy. Optical techniques were refined and applied to relate the light-scattering properties of RBCs to obtain a quantitative index of aggregate size ( G), which, under idealized conditions, represents the number of RBCs per aggregate. WBC margination, defined as the radial migration of WBCs to the venular wall and their subsequent rolling along the endothelium, was measured as the percentage of the potentially maximal WBC volumetric flux within the microvessel lumen ( F WBC ∗). In normal blood, F WBC ∗ increased exponentially fourfold, and G increased from 1 to 1.15 as wall shear rates (γ˙) were reduced from a steady-state value of ∼600 to <100 s−1 by proximal occlusion with a blunt microprobe. Enhancement of aggregation by infusion (iv) of dextran 500 (428 kDa), to attain a systemic concentration of 3 g/100 ml, resulted in a four- and sevenfold increase in G and F WBC ∗, respectively, as γ˙was reduced below 100 s−1. Inhibition of RBC aggregation by infusion of dextran 40 (37.5 kDa) caused F WBC ∗ to fall to one-half of its steady-state level for γ˙ < 100 s−1. Thus it appears that the well-known increase of WBC margination with reductions in γ˙ is strongly dependent on the occurrence of RBC aggregation. Increasing the extent of RBC aggregation during reductions in γ˙ also increased the firm adhesion of WBCs to the endothelium because of an enhanced probability of contact between leukocytes and the postcapillary venular wall.

Role of myosin phosphorylation in contractility of a platelet aggregate

1985 ◽  
Vol 249 (3) ◽  
pp. C297-C303 ◽  
Author(s):  
M. E. Bromberg ◽  
R. W. Sevy ◽  
J. L. Daniel ◽  
L. Salganicoff
Keyword(s):  
Steady State ◽  
Light Chain ◽  
Myosin Phosphorylation ◽  
Nonmuscle Cells ◽  
Platelet Aggregate ◽  
Steady State Levels ◽  
State Contraction ◽  
The Relationship ◽  
Dose Dependent

The relationship between tension and myosin 20,000-Da light chain phosphorylation in intact nonmuscle cells was investigated using a preparation of thrombin-activated, irreversibly aggregated platelets known as the platelet strip. Steady-state levels of tension generated by the platelet strip were found to be linearly related to the level of myosin phosphorylation. This relationship was observed during dose-dependent relaxation induced by the adenylate cyclase activators prostaglandin (PG) E1 and PGI2, and during contraction induced by ADP, epinephrine, and the prostaglandin endoperoxide analogue U-46619, which did not appreciably alter the basal level of adenosine 3',5'-cyclic monophosphate in the preparation. The fully relaxed platelet strip, in the absence of external Ca2+, was associated with a level of 12% light chain phosphorylation, which increased to 72% on maximal contraction. During both relaxation and contraction, changes in myosin phosphorylation were also found to precede or coincide with tension changes. Furthermore, steady-state contraction induced by ADP was associated with a maintained elevation in the level of myosin phosphorylation. These results support the concept that myosin phosphorylation is an important regulatory mechanism for contractility in platelets.

scholarly journals Role of Human Sec63 in Modulating the Steady-State Levels of Multi-Spanning Membrane Proteins

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e49243 ◽  
Author(s):  
Andreas Mades ◽  
Katherina Gotthardt ◽  
Karin Awe ◽  
Jens Stieler ◽  
Tatjana Döring ◽  
...  
Keyword(s):  
Steady State ◽  
Membrane Proteins ◽  
Steady State Levels

scholarly journals Cyclin-Dependent Kinase Activity Is Required for Efficient Expression and Posttranslational Modification of Human Cytomegalovirus Proteins and for Production of Extracellular Particles

2006 ◽  
Vol 80 (12) ◽  
pp. 5886-5896 ◽  
Author(s):  
Veronica Sanchez ◽  
Deborah H. Spector
Keyword(s):  
Steady State ◽  
Human Cytomegalovirus ◽  
Virus Titer ◽  
State Level ◽  
Early Gene ◽  
Tegument Protein ◽  
Cyclin Dependent Kinase ◽  
Viral Dna ◽  
Infected Cells ◽  
Steady State Levels

ABSTRACT We have previously shown that the addition of the cyclin-dependent kinase (cdk) inhibitor Roscovitine at the beginning of infection of cells with human cytomegalovirus (HCMV) significantly disrupts immediate-early gene expression and the progression of the infection. In the present study, we have examined the effects of cdk inhibition on late viral events by delaying addition of Roscovitine until 24 h postinfection. Although viral DNA replication was inhibited two- to threefold by treatment of infected cells with Roscovitine, the drop did not correspond to the 1- to 2-log-unit decrease in virus titer. Quantification of viral DNA in the supernatant from cells revealed that there was a significant reduction in the production or release of extracellular particles. We observed a lag in the expression of several viral proteins but there was a significant decrease in the steady-state levels of IE2-86. Likewise, the steady-state level of the essential tegument protein UL32 (pp150) was reduced. The levels of pp150 and IE2-86 mRNA were not greatly affected by treatment with Roscovitine and thus did not correlate with the reduced levels of protein. In contrast, the expression of the tegument protein ppUL69 was higher in drug-treated samples, and the protein accumulated in a hyperphosphorylated form. ppUL69 localized to intranuclear aggregates that did not overlap with viral replication centers in cells treated with Roscovitine. Taken together, these data indicate that cdk activity is required at multiple steps during HCMV infection, including the expression, modification, and localization of virus-encoded proteins.

Steady-state level of kit ligand mRNA in goat ovaries and the role of kit ligand in preantral follicle survival and growth in vitro

2009 ◽  
Vol 77 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Juliana J.H. Celestino ◽  
Jamily B. Bruno ◽  
Isabel B. Lima-Verde ◽  
Maria Helena T. Matos ◽  
Mércia Viviane A. Saraiva ◽  
...  
Keyword(s):  
Steady State ◽  
State Level ◽  
Steady State Level ◽  
Preantral Follicle ◽  
Kit Ligand ◽  
Survival And Growth

Steady-State Serum Concentrations of Dothiepin and Northiaden after Two Dosage Regimens of Dothiepin Hydrochloride (Prothiaden)

1973 ◽  
Vol 1 (2) ◽  
pp. 391-397
Author(s):  
B R S Nakra ◽  
R C Glass ◽  
J A Rees
Keyword(s):  
Steady State ◽  
Parent Drug ◽  
State Level ◽  
Serum Levels ◽  
Single Daily Dose ◽  
Serum Concentrations ◽  
Dosage Regimens ◽  
Daily Dose ◽  
Steady State Serum ◽  
Steady State Levels

Five healthy volunteers took part in a crossover study which examined the serum concentrations of dothiepin and northiaden after a 25 mg three times a day and a 75 mg once a day dosage regimen of Prothiaden. The inter-individual variation of serum levels was large after either schedule which is to be expected with this group of drugs. The minimum steady-state level of dothiepin tended to be lower after the single daily dose, but the differences were small and not statistically significant. The approximate maximum steady-state levels of dothiepin showed large intra- and inter-subject variation and no obvious trend. The values of the desmethylated metabolite, northiaden, tended to follow the dothiepin concentrations but were lower than the parent drug. Average steady-state levels tended, with one exception, to be very similar after both regimens with no evidence of any trend when comparing the two regimens. The study showed that the two regimens yielded similar steady-state serum concentrations both of drug and metabolite but inter-individual differences were large.

scholarly journals An orthogonal c-Cbl recognition mode targets LynA for rapid degradation and builds specificity into the LynA checkpoint

2019 ◽  
Author(s):  
Ben F. Brian ◽  
Myra G. Nunez ◽  
Kathryn L. Schwertfeger ◽  
Tanya S. Freedman
Keyword(s):  
Steady State ◽  
Ubiquitin Ligase ◽  
Biochemical Analysis ◽  
Cell Activation ◽  
Critical Factor ◽  
Myeloid Cell ◽  
State Level ◽  
Cell Specificity ◽  
Steady State Levels ◽  
Insert Region

AbstractThe activity of Src-family kinases (SFKs), which phosphorylate immunoreceptor tyrosine-based activation motifs (ITAMs), is critical factor regulating myeloid-cell activation. In a previous paper (Freedman et al., 2015) we showed in macrophages that the SFK LynA is uniquely susceptible to rapid ubiquitin-mediated degradation, functioning as a rheostat regulating ITAM signaling. We now report the mechanism by which LynA is preferentially targeted for degradation and how cell specificity is built into the LynA rheostat. Using genetic and biochemical analysis, we found that the E3 ubiquitin ligase c-Cbl preferentially targets LynA via tyrosine 32 in its unique insert region. This orthogonal mode of c-Cbl recognition depresses the steady-state level of macrophage LynA. Mast cells, however, express little c-Cbl and have correspondingly high steady-state levels of LynA. Upon activation, mast-cell LynA is not rapidly degraded, and SFK-mediated signaling is amplified relative to macrophages. Cell-specific c-Cbl expression therefore builds cell specificity into the LynA checkpoint.

Role of adenovirus E1B proteins in transformation: altered organization of intermediate filaments in transformed cells that express the 19-kilodalton protein

1990 ◽  
Vol 10 (1) ◽  
pp. 120-130
Author(s):  
E White ◽  
R Cipriani
Keyword(s):  
Intermediate Filaments ◽  
Expression Vectors ◽  
Transformed Cells ◽  
Gene Products ◽  
Primary Cells ◽  
Subsequent Growth ◽  
Protein Functions ◽  
Adenovirus E1b

Cooperation of the nuclear oncogene E1A with the E1B oncogene is required for transformation of primary cells. Expression vectors were constructed to produce the 19-kilodalton (19K) and 55K E1B proteins under the direction of heterologous promoters in order to investigate the role of individual E1B proteins in transformation. Coexpression of E1A and either the 19K or 55K E1B gene products was sufficient for the formation of transformed foci in primary rat cells at half the frequency of an intact E1B gene, suggesting that the 19K and 55K proteins function via independent pathways in transformation. Furthermore, the effects of Ha-ras and the E1B 19K gene product were additive when cotransfected with E1A, suggesting that the 19K protein functions in transformation by a mechanism independent from that of ras as well. Although expression of E1A and either E1B protein was sufficient for the subsequent growth of cells in long-term culture, the 19K protein was required to support growth in semisolid media. As the 19K protein has been shown to associate with and disrupt intermediate filaments (IFs) when transiently expressed with plasmid vectors (E. White and R. Cipriani, Proc. Natl. Acad. Sci. USA, 86:9886-9890, 1989), the organization of IFs in transformed cells was investigated. Primary rat cells transformed by plasmids encoding E1A plus the E1B 19K protein showed gross perturbations of IFs, whereas cell lines transformed by plasmids encoding E1A plus the E1B 55K protein or E1A plus Ha-ras did not. These results suggest that an intact IF cytoskeleton may inhibit anchorage-independent growth and that the E1B 19K protein can overcome this inhibition by disrupting the IF cytoskeleton.

Sign in / Sign up

Export Citation Format

Share Document