Ms 2007 Activator

[Karon Howey]

ReKlaimremoves biological and atmospheric staining from vertical or horizontal masonry surfaces and cleans difficult mold and mildew staining on limestone, unpolished marble, concrete and other masonry in humid environments. This two-component system includes a cleaner and an activator. Treated surfaces are neutralized with Sure Klean Limestone & Masonry Afterwash.

Enviro Klean ReKlaim safely removes biological and atmospheric staining from vertical or horizontal masonry surfaces, and cleans difficult mold and mildew staining that blackens limestone, unpolished marble, concrete and other masonry surfaces in humid environments. The two-component ReKlaim system includes a liquid cleaner and a liquid activator. Treated surfaces are neutralized with a solution of Sure Klean Limestone & Masonry Afterwash diluted 1:1 with clean water. Effectively removes light-to-severe staining without damage to the surface or the environment caused by more conventional cleaning methods.

3) Kim et al. 2008. Epidermal growth factor-induced enhancement of glioblatoma cell migration in 3D arises from an intrinsic increase in speed but an extrinsic matrix- and proteolysis-dependent increase in persistence. Mol Bio Cell. 19, 4249-4259.

The concentration of CN02 activator required for efficient activation of Rac and Cdc42 proteins can vary between cell types and whether the medium contains serum or not. In addition, the length of treatment can be manipulated to yield a moderate or robust activation (see Tables 1 and 2). For these reasons, the concentration of this reagent and the duration of treatment should be determined by the user. Typically the effective range is between 0.1 units / ml and 1.0 unit / ml for incubation in serum free medium. In media containing serum it might be difficult to observe the difference between CN02 treated versus untreated samples because there are activators in the serum added to cultured cells. Inconjunction, incubation times of 1 to 10 min should be tested for each cell type. Recommended conditions for several cell types are detailed in Tables 1 and 2.

Table 1. Suggested Conditions for Rac activation in serum free medium. The indicated cells were subjected to Rac activation assay with CN02 in serum free medium. Serum containing medium will cause activation in all samples which will override effects seen by CN02 alone. Optimal conditions were determined by manipulating reagent concentration and duration of treatment.

1. A moderate phenotype is characterized by a 80-150% increase in Rac activity accompanied by ruffles and lamellipodia formation (see Figure 2b). A robust phenotype is characterized by >200% increase in Rac activity accompanied by a similar ruffles and lamellipodia formation.

Swiss 3T3 fibroblasts plated on coverslips at 1000 cells / cm2 and grown for two days in DMEM plus 10% fetal calf serum at 37C and 5% CO2, were serum starved for 16 h in media containing 1% serum and 8 h in 0% serum media. Cultures were treated with 5 l of CN02 per ml of medium for 10 min at 37C. Cells were then fixed, stained with rhodamine-labeled phalloidin (Cat. # PHDR1 or BK005), and visualized by fluorescence microscopy. Images were taken at a magnification of 40. The untreated control cells were treated with 5ul sterile PBS per ml of medium. The cells treated with CN02 produced abundant ruffles and lamellipodia whereas the control had less than 10% of CN02 levels of similar actin structures. Under similar conditions the activity of Cdc42 and Rac increased by 50 and 130% respectively as measured by the G-LISATM Activation Assays (Cat.# BK127 and BK125 resp.). A = serum starved cell, 2 s exposure; B = example Rac activation, 0.3 s exposure

For product Datasheets and MSDSs please click on the PDF links below. For additional information, click on the FAQs tab above or contact our Technical Support department at tser...@cytoskeleton.com

The activity of activators can be regulated. Some activators have an allosteric site and can only function when a certain molecule binds to this site, essentially turning the activator on.[4] Post-translational modifications to activators can also regulate activity, increasing or decreasing activity depending on the type of modification and activator being modified.[1]

Activator proteins consist of two main domains: a DNA-binding domain that binds to a DNA sequence specific to the activator, and an activation domain that functions to increase gene transcription by interacting with other molecules.[1] Activator DNA-binding domains come in a variety of conformations, including the helix-turn-helix, zinc finger, and leucine zipper among others.[1][2][3] These DNA-binding domains are specific to a certain DNA sequence, allowing activators to turn on only certain genes.[1][2][3] Activation domains also come in a variety of types that are categorized based on the domain's amino acid sequence, including alanine-rich, glutamine-rich, and acidic domains.[1] These domains are not as specific, and tend to interact with a variety of target molecules.[1]

Within the grooves of the DNA double helix, functional groups of the base pairs are exposed.[2] The sequence of the DNA thus creates a unique pattern of surface features, including areas of possible hydrogen bonding, ionic bonding, as well as hydrophobic interactions.[2] Activators also have unique sequences of amino acids with side chains that are able to interact with the functional groups in DNA.[2][3] Thus, the pattern of amino acid side chains making up an activator protein will be complementary to the surface features of the specific DNA regulatory sequence it was designed to bind to.[1][2][3] The complementary interactions between the amino acids of the activator protein and the functional groups of the DNA create an "exact-fit" specificity between the activator and its regulatory DNA sequence.[2]

Activator-binding sites may be located very close to the promoter or numerous base pairs away.[2][3] If the regulatory sequence is located far away, the DNA will loop over itself (DNA looping) in order for the bound activator to interact with the transcription machinery at the promoter site.[2][3]

In prokaryotes, multiple genes can be transcribed together (operon), and are thus controlled under the same regulatory sequence.[2] In eukaryotes, genes tend to be transcribed individually, and each gene is controlled by its own regulatory sequences.[2] Regulatory sequences where activators bind are commonly found upstream from the promoter, but they can also be found downstream or even within introns in eukaryotes.[1][2][3]

Binding of the activator to its regulatory sequence promotes gene transcription by enabling RNA polymerase activity.[1][2][3][4] This is done through various mechanisms, such as recruiting transcription machinery to the promoter and triggering RNA polymerase to continue into elongation.[1][2][3][4]

Activator interactions with RNA polymerase are mostly direct in prokaryotes and indirect in eukaryotes.[2] In prokaryotes, activators tend to make contact with the RNA polymerase directly in order to help bind it to the promoter.[2] In eukaryotes, activators mostly interact with other proteins, and these proteins will then be the ones to interact with the RNA polymerase.[2]

In prokaryotes, genes controlled by activators have promoters that are unable to strongly bind to RNA polymerase by themselves.[2][3] Thus, activator proteins help to promote the binding of the RNA polymerase to the promoter.[2][3] This is done through various mechanisms. Activators may bend the DNA in order to better expose the promoter so the RNA polymerase can bind more effectively.[3] Activators may make direct contact with the RNA polymerase and secure it to the promoter.[2][3][4]

In eukaryotes, activators have a variety of different target molecules that they can recruit in order to promote gene transcription.[1][2] They can recruit other transcription factors and cofactors that are needed in transcription initiation.[1][2]

Activators can recruit molecules known as coactivators.[1][2] These coactivator molecules can then perform functions necessary for beginning transcription in place of the activators themselves, such as chromatin modifications.[1][2]

DNA is much more condensed in eukaryotes; thus, activators tend to recruit proteins that are able to restructure the chromatin so the promoter is more easily accessible by the transcription machinery.[1][2] Some proteins will rearrange the layout of nucleosomes along the DNA in order to expose the promoter site (ATP-dependent chromatin remodeling complexes).[1][2] Other proteins affect the binding between histones and DNA via post-translational histone modifications, allowing the DNA tightly wrapped into nucleosomes to loosen.[1][2]

There are different ways in which the activity of activators themselves can be regulated, in order to ensure that activators are stimulating gene transcription at appropriate times and levels.[1] Activator activity can increase or decrease in response to environmental stimuli or other intracellular signals.[1]

Activators often must be "turned on" before they can promote gene transcription.[2][3][4] The activity of activators is controlled by the ability of the activator to bind to its regulatory site along the DNA.[2][3][4] The DNA-binding domain of the activator has an active form and an inactive form, which are controlled by the binding of molecules known as allosteric effectors to the allosteric site of the activator.[4]

Activators in their inactive form are not bound to any allosteric effectors.[4] When inactive, the activator is unable to bind to its specific regulatory sequence in the DNA, and thus has no regulatory effect on the transcription of genes.[4]

When an allosteric effector binds to the allosteric site of an activator, a conformational change in the DNA-binding domain occurs, which allows the protein to bind to the DNA and increase gene transcription.[2][4]

3a8082e126