SSK1
目录号 : GC63202
SSK1，是一种衰老特异性杀伤化合物，是一种 β-galactosidase 靶向前药，可减轻炎症。SSK1 被溶酶体 β-galactosidase 激活，并通过激活 p38 MAPK 和诱导细胞凋亡 (apoptosis) 选择性杀死衰老细胞。
Cas No.:2629250-69-5
Sample solution is provided at 25 µL, 10mM.
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Quality Control & SDS
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- Purity: >99.00%
- COA (Certificate Of Analysis)
- SDS (Safety Data Sheet)
- Datasheet
SSK1, a senescence-specific killing compound, is a β-galactosidase-targeted prodrug attenuates inflammation. SSK1 is activated by lysosomal β-galactosidase and selectively killed senescent cells through the activation of p38 MAPK and induction of apoptosis[1].
SSK1 (0.5 µM; 12-72 hours) activates the phosphorylation levels of both p38 MAPK and MKK3/MKK6 in senescent cells. SSK1 kills senescent cells through the activation of the p38 MAPK signaling pathway. SSK1 is able to induce mitochondrial DNA damage in senescent cells[1]. SSK1 (0.01-1 µM; 3 days) selectively and potently eliminates β-galactosidase-positive senescent cells within a wide therapeutic window[1].
SSK1 (0.5 mg/kg; i.p.; two days every week; for four weeks) could eliminate senescent cells and decrease senescence-associated markers in lung-injured mice[1].In aged mice (20-month-old), SSK1 (0.5 mg/kg; 3 days every 2 weeks for 8 weeks) effectively clears senescent cells in different tissues, decreases the senescence- and age-associated gene signatures, attenuates low-grade local and systemic inflammation, and restores physical function[1].
[1]. Yusheng Cai, et al. Elimination of senescent cells by β-galactosidase-targeted prodrug attenuates inflammation and restores physical function in aged mice. Cell Res. 2020 Jul;30(7):574-589.
| Cas No. | 2629250-69-5 | SDF | |
| 分子式 | C31H34F2N4O18 | 分子量 | 788.61 |
| 溶解度 | DMSO : 200 mg/mL (253.61 mM; Need ultrasonic) | 储存条件 | 4°C, away from moisture and light |
| General tips | 请根据产品在不同溶剂中的溶解度选择合适的溶剂配制储备液；一旦配成溶液，请分装保存，避免反复冻融造成的产品失效。 储备液的保存方式和期限：-80°C 储存时，请在 6 个月内使用，-20°C 储存时，请在 1 个月内使用。 为了提高溶解度，请将管子加热至37℃，然后在超声波浴中震荡一段时间。 |
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| Shipping Condition | 评估样品解决方案：配备蓝冰进行发货。所有其他可用尺寸：配备RT，或根据请求配备蓝冰。 | ||
| 制备储备液 | |||
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1 mg | 5 mg | 10 mg |
| 1 mM | 1.2681 mL | 6.3403 mL | 12.6805 mL |
| 5 mM | 0.2536 mL | 1.2681 mL | 2.5361 mL |
| 10 mM | 0.1268 mL | 0.634 mL | 1.2681 mL |
| 第一步：请输入基本实验信息（考虑到实验过程中的损耗，建议多配一只动物的药量） | ||||||||||
| 给药剂量 | mg/kg |  |
动物平均体重 | g | |
每只动物给药体积 | ul | |
动物数量 | 只 |
| 第二步：请输入动物体内配方组成（配方适用于不溶于水的药物；不同批次药物配方比例不同，请联系GLPBIO为您提供正确的澄清溶液配方） | ||||||||||
| % DMSO % % Tween 80 % saline | ||||||||||
| 计算重置 | ||||||||||
计算结果:
工作液浓度： mg/ml；
DMSO母液配制方法： mg 药物溶于 μL DMSO溶液（母液浓度 mg/mL，
体内配方配制方法：取 μL DMSO母液，加入 μL PEG300，混匀澄清后加入μL Tween 80，混匀澄清后加入 μL saline，混匀澄清。
1. 首先保证母液是澄清的；
2.
一定要按照顺序依次将溶剂加入，进行下一步操作之前必须保证上一步操作得到的是澄清的溶液，可采用涡旋、超声或水浴加热等物理方法助溶。
3. 以上所有助溶剂都可在 GlpBio 网站选购。
Elimination of senescent cells by β-galactosidase-targeted prodrug attenuates inflammation and restores physical function in aged mice
Cell Res 2020 Jul;30(7):574-589.PMID:32341413DOI:10.1038/s41422-020-0314-9.
Cellular senescence, a persistent state of cell cycle arrest, accumulates in aged organisms, contributes to tissue dysfunction, and drives age-related phenotypes. The clearance of senescent cells is expected to decrease chronic, low-grade inflammation and improve tissue repair capacity, thus attenuating the decline of physical function in aged organisms. However, selective and effective clearance of senescent cells of different cell types has proven challenging. Herein, we developed a prodrug strategy to design a new compound based on the increased activity of lysosomal β-galactosidase (β-gal), a primary characteristic of senescent cells. Our prodrug SSK1 is specifically activated by β-gal and eliminates mouse and human senescent cells independently of senescence inducers and cell types. In aged mice, our compound effectively cleared senescent cells in different tissues, decreased the senescence- and age-associated gene signatures, attenuated low-grade local and systemic inflammation, and restored physical function. Our results demonstrate that lysosomal β-gal can be effectively leveraged to selectively eliminate senescent cells, providing a novel strategy to develop anti-aging interventions.
Phosphorylated SSK1 prevents unphosphorylated SSK1 from activating the Ssk2 mitogen-activated protein kinase kinase kinase in the yeast high-osmolarity glycerol osmoregulatory pathway
Mol Cell Biol 2008 Sep;28(17):5172-83.PMID:18573873DOI:10.1128/MCB.00589-08.
In Saccharomyces cerevisiae, external high osmolarity activates the Hog1 mitogen-activated protein kinase (MAPK), which controls various aspects of osmoadaptation. SSK1 is a homolog of bacterial two-component response regulators and activates the Ssk2 MAPK kinase kinase upstream of Hog1. It has been proposed that unphosphorylated SSK1 (Ssk1-OH) is the active form and that SSK1 phosphorylated (SSK1 approximately P) at Asp554 by the Sln1-Ypd1-Ssk1 multistep phosphorelay mechanism is the inactive form. In this study, we show that constitutive activation of Ssk2 occurs when SSK1 phosphorylation is blocked by either an SSK1 mutation at the phosphorylation site or an SSK1 mutation that inhibits its interaction with Ypd1, the donor of phosphate to SSK1. Thus, Ssk1-OH is indeed necessary for Ssk2 activation. However, overexpression of wild-type SSK1 or of an SSK1 mutant that cannot bind Ssk2 prevents constitutively active SSK1 mutants from activating Ssk2. Therefore, SSK1 has a dual function as both an activator of Ssk2 and an inhibitor of SSK1 itself. We also found that SSK1 exists mostly as a dimer within cells. From mutant phenotypes, we deduce that only the Ssk1-OH/Ssk1-OH dimer can activate Ssk2 efficiently. Hence, because SSK1 approximately P binds to and inhibits Ssk1-OH, moderate fluctuation of the level of Ssk1-OH does not lead to nonphysiological and detrimental activation of Hog1.
Delayed Turnover of Unphosphorylated SSK1 during Carbon Stress Activates the Yeast Hog1 Map Kinase Pathway
PLoS One 2015 Sep 4;10(9):e0137199.PMID:26340004DOI:10.1371/journal.pone.0137199.
In Saccharomyces cerevisiae, the Hog1 mitogen-activated protein kinase (MAPK) pathway coordinates the adaptation to osmotic stress and was recently reported to respond to acute changes in glucose levels. Similarly as in osmotic stress, glucose starvation leads to a transient accumulation of Hog1 in the nucleus. However, the kinetics and the mechanism of Hog1 activation are different for these stress conditions. During osmotic shock the activation of Hog1 can be transduced by either the Sho1 or the Sln1/Ypd1/SSK1 branch. During glucose starvation the phosphorylation of Hog1 is slower and is completely dependent on SSK1, but independent of Sho1. To characterize the mechanism of activation of Hog1 during carbon stress, we examined the turnover of SSK1 protein levels upon glucose starvation in the presence of cycloheximide and monitored protein levels by western blotting. Our data demonstrate that unphosphorylated SSK1 was quickly degraded during exponential growth and after osmotic stress but remained remarkably stable during glucose limitation. We conclude that glucose starvation induces a delay in the turnover of unphosphorylated SSK1, which is sufficient to activate the Hog1 MAPK pathway. Although unphosphorylated SSK1 is known to be degraded by the proteasome, its stabilization is apparently not due to changes in cellular localization or decrease in ubiquitination levels during glucose limitation.
How the Pathogenic Fungus Alternaria alternata Copes with Stress via the Response Regulators SSK1 and SHO1
PLoS One 2016 Feb 10;11(2):e0149153.PMID:26863027DOI:10.1371/journal.pone.0149153.
The tangerine pathotype of Alternaria alternata is a necrotrophic fungal pathogen causing brown spot disease on a number of citrus cultivars. To better understand the dynamics of signal regulation leading to oxidative and osmotic stress response and fungal infection on citrus, phenotypic characterization of the yeast SSK1 response regulator homolog was performed. It was determined that SSK1 responds to diverse environmental stimuli and plays a critical role in fungal pathogenesis. Experiments to determine the phenotypes resulting from the loss of SSK1 reveal that the SSK1 gene product may be fulfilling similar regulatory roles in signaling pathways involving a HOG1 MAP kinase during ROS resistance, osmotic resistance, fungicide sensitivity and fungal virulence. The SSK1 mutants display elevated sensitivity to oxidants, fail to detoxify H2O2 effectively, induce minor necrosis on susceptible citrus leaves, and displays resistance to dicarboximide and phenylpyrrole fungicides. Unlike the SKN7 response regulator, SSK1 and HOG1 confer resistance to salt-induced osmotic stress via an unknown kinase sensor rather than the "two component" histidine kinase HSK1. SSK1 and HOG1 play a moderate role in sugar-induced osmotic stress. We also show that SSK1 mutants are impaired in their ability to produce germ tubes from conidia, indicating a role for the gene product in cell differentiation. SSK1 also is involved in multi-drug resistance. However, deletion of the yeast SHO1 (synthetic high osmolarity) homolog resulted in no noticeable phenotypes. Nonetheless, our results show that A. alternata can sense and react to different types of stress via SSK1, HOG1 and SKN7 in a cooperative manner leading to proper physiological and pathological functions.
Effects of osmolytes on the SLN1-YPD1-SSK1 phosphorelay system from Saccharomyces cerevisiae
Biochemistry 2009 Aug 25;48(33):8044-50.PMID:19618914DOI:10.1021/bi900886g.
The multistep His-Asp phosphorelay system in Saccharomyces cerevisiae allows cells to adapt to osmotic, oxidative, and other environmental stresses. The pathway consists of a hybrid histidine kinase SLN1, a histidine-containing phosphotransfer (HPt) protein YPD1, and two response regulator proteins, SSK1 and SKN7. Under nonosmotic stress conditions, the SLN1 sensor kinase is active, and phosphoryl groups are shuttled through YPD1 to SSK1, therefore maintaining the response regulator protein in a constitutively phosphorylated state. The cellular response to hyperosmotic stress involves rapid efflux of water and changes in intracellular ion and osmolyte concentration. In this study, we examined the individual and combined effects of NaCl and glycerol on phosphotransfer rates within the SLN1-YPD1-SSK1 phosphorelay. The results show that the combined effects of glycerol and NaCl on the phosphotransfer reaction rates are different from the individual effects of glycerol and NaCl. The combinatory effect is likely more representative of the in vivo changes that occur during hyperosmotic stress. In addition, the effect of osmolyte concentration on the half-life of the phosphorylated SSK1 receiver domain in the presence/absence of YPD1 was evaluated. Our findings demonstrate that increasing osmolyte concentrations negatively affect the YPD1 x SSK1-P interaction, thereby facilitating dephosphorylation of SSK1 and activating the HOG1 MAP kinase cascade. In contrast, at the highest osmolyte concentrations, reflective of the osmoadaptation phase of the signaling pathway, the kinetics of the phosphorelay favor production of SSK1-P and inhibition of the HOG1 pathway.