Phospho-SRF (Ser77) Antibody
Description
Introduction to Phospho-SRF (Ser77) Antibody
Phospho-SRF (Ser77) antibodies are rabbit-derived polyclonal antibodies designed to selectively recognize SRF proteins phosphorylated at serine 77. These antibodies enable researchers to investigate SRF activation dynamics, particularly in studies involving cytoskeletal regulation, cardiac development, and cellular response to growth signals .
Biological Context of SRF and Ser77 Phosphorylation
SRF Function:
SRF binds serum response elements (SREs) in promoters of genes like FOS, regulating cytoskeletal dynamics, cell migration, and cardiac maturation. Its activity is modulated by Rho GTPase signaling and actin polymerization .
Phosphorylation at Ser77:
-
Enzyme Involvement: Phosphorylation at Ser77 is mediated by casein kinase II (CSNK2A1, UniProt: P68400) .
-
Regulatory Role: This modification influences SRF’s interaction with coactivators like MRTFA, linking cytoskeletal changes to gene expression .
Research Applications
-
Mechanistic Studies: Used to explore SRF’s role in Rho GTPase signaling and actin-dependent transcription .
-
Disease Models: Applied in cardiac differentiation studies and cancer research (e.g., viral carcinogenesis pathways) .
-
Techniques:
Target Protein Overview
Validation and Quality Control
Product Specs
Target Background
- miR-647 acts as a tumor metastasis suppressor in gastric cancer by targeting the SRF/MYH9 axis. PMID: 28900514
- Research suggests that miR-101-3p suppresses HOTAIR-induced proliferation and invasion by directly targeting SRF in gastric carcinoma cells. PMID: 28251884
- SRF contributes to GC metastasis by facilitating myofibroblast-cancer cell crosstalk. PMID: 27323859
- Elevated SRF expression is associated with breast cancer. PMID: 26885614
- Studies have identified SRF as one of the transcription factors responsible for docetaxel-resistant prostate cancer. Docetaxel treatment increases SRF's transcriptional activity, and its knockdown re-sensitizes resistant cells to docetaxel. PMID: 28249598
- NANOG reactivates the ROCK and Transforming Growth Factor (TGF)-beta pathways, both impaired in senescent cells, leading to ACTIN polymerization, MRTF-A translocation into the nucleus, and serum response factor (SRF)-dependent myogenic gene expression. PMID: 27350449
- HOTAIR is regulated by the RhoC-MRTF-A-SRF signaling pathway in breast cancer cells. PMID: 28069441
- Findings indicate a role for Galphaq and/or Galpha14 in CCR2a/CCR2b-stimulated Rho A GTPase-mediated serum response factor activation. PMID: 26823487
- A blood pressure-associated polymorphism controls ARHGAP42 expression through serum response factor DNA binding. PMID: 28112683
- A subset of cellular variants of myofibroma and myopericytoma, exhibiting a smooth muscle-like immunophenotype, harbors recurrent SRF-RELA gene fusions, mimicking sarcomas with myogenic differentiation. PMID: 28248815
- SRF has been identified as a novel target gene for miR-22, as evidenced by luciferase reporter assay. Knockdown of SRF can lead to endothelial dysfunction. PMID: 28161397
- miR-181a/b is among the factors involved in VSMC differentiation toward a synthetic phenotype through targeting SR. PMID: 27911586
- miR-483-3p is upregulated in Endothelial progenitor cells (EPCs) from deep vein thrombosis patients, and it targets SRF to decrease EPCs migration and tube formation. PMID: 26801758
- ADGRG2 constitutively activates RhoA-SRE pathways. PMID: 26321231
- FLNA functions as a positive cellular transducer, linking actin polymerization to MKL1-SRF activity and counteracting the known repressive complex of MKL1 and monomeric G-actin. PMID: 26554816
- The SRF-IL6 axis is the critical mediator of YAP-induced stemness in mammary epithelial cells and breast cancer. PMID: 26671411
- Data indicate that microRNA miR-320a is a key regulator of rtherogenesis, down-regulating serum response factor (SRF). PMID: 25728840
- These findings suggest a central role for the SRF/MRTF pathway in the pathobiology of lung fibrosis. PMID: 25681733
- STAT3 protein regulates vascular smooth muscle cell phenotypic switch through interaction with myocardin and SRF. PMID: 26100622
- High levels of Myc engage Miz1 in repressive DNA binding complexes and suppress an SRF-dependent transcriptional program that supports epithelial cell survival. PMID: 25896507
- SRF regulates neutrophil migration, integrin activation, and trafficking. Disruption of the SRF pathway results in myelodysplasia and immune dysfunction. PMID: 25402621
- Methylation changes in GFRA1, SRF, and ZNF382 may serve as a potential biomarker set for predicting gastric carcinoma metastasis. PMID: 25009298
- SRF promotes gastric cancer metastasis and the epithelial to mesenchymal transition through miR-199a-5p-mediated downregulation of E-cadherin. PMID: 25080937
- A study explored a new therapeutic alternative for treating multiresistant lung adenocarcinoma via siRNA-specific transfection of six crucial molecules involved in lung carcinogenesis: SFR, E2F1, Survivin, HIF1, HIF2, and STAT3. PMID: 24627437
- Research suggests that SRF is critical for HCC to acquire a mesenchymal phenotype, leading to resistance against sorafenib-mediated apoptotic effects. PMID: 24173109
- A dilated cardiomyopathy-associated FHOD3 variant impairs the ability to induce activation of transcription factor serum response factor. PMID: 24088304
- Findings demonstrate that serum response factor (SRF) nuclear expression in castration-resistant prostate cancer bone metastases is associated with survival, with patients exhibiting the shortest survival showing high SRF nuclear expression and patients with the longest survival having low SRF nuclear expression. PMID: 24249383
- Androgen-responsive SRF target genes influence CaP cell behavior. PMID: 23576568
- The RhoA signaling axis, a well-known upstream stimulator of SRF action that harbors drugable targets, conveyed androgen-responsiveness to SRF. PMID: 23469924
- Transfection of NSCLC cell lines with specific siRNAs against SRF, E2F1, and survivin resulted in a significant reduction in intracellular mRNA concentration. PMID: 23152437
- Itk enhances Galpha13 mediated activation of serum response factor (SRF) transcriptional activity, dependent on its ability to interact with Galpha13, although its kinase activity is not required for this enhancement. PMID: 23454662
- Substitution of any of the TFBS from our particular search of MEF2, CREB, and SRF significantly decreased the number of identified clusters. PMID: 23382855
- High expression of serum response factor is associated with gastric carcinoma. PMID: 23134219
- Upon neuronal injury through facial nerve transection, constitutively active SRF enhances motorneuron survival. PMID: 22537405
- Dysfunction or loss of the SRF-activating mitogen-associated kinase pathway under stress conditions in transgenic mice may be part of Parkinson's disease etiology. PMID: 22356487
- Lmod1 is a new SMC-restricted SRF/MYOCD target gene. PMID: 22157009
- Downregulation of the MRTF-SRF axis activity and the expression of muscle-specific microRNAs, particularly miR-1, may contribute to COPD-associated skeletal muscle dysfunction. PMID: 21998125
- Overexpression of serum response factor in hepatocellular carcinoma may play a significant role in tumor cell migration and invasion through upregulation of matrix metalloproteinase-2 and matrix metalloproteinase-9. PMID: 21842128
- RTVP-1 contributes to the effect of serum response factor on glioma cell migration. PMID: 21777672
- Data indicate that serum response factor (SRF) is one of the target genes of miR-483-5p. PMID: 21893058
- SRF can gain nuclear entry through an auxiliary, nuclear localization sequence-independent mechanism. PMID: 21131446
- These findings identify serum response factor as a host cell transcription factor that regulates immediate early gene expression in Toxoplasma-infected cells. PMID: 21479245
- SRF pathway alterations are linked to insulin resistance, may contribute to type 2 diabetes pathogenesis, and could represent therapeutic targets. PMID: 21393865
- Data reveal that serum response factor is a novel interferon (IFN)gamma-regulated gene and further elucidate the molecular pathway between IFNgamma, IFNgamma-regulated genes, and SRF and its target genes. PMID: 20685657
- Two transcription factors, SRF and TFAP2, as well as an intronic element encompassing EGR3-like sequence, work together to regulate the expression of the FXN gene. PMID: 20808827
- SRF depletion affects the expansion of the high and low differentiation grade HCC cells HepG2 and JHH6. PMID: 20144681
- Data show that serum response factor is an essential regulator of primary human vascular smooth muscle cell proliferation and senescence. PMID: 20096952
Q&A
What is SRF and why is its phosphorylation at Ser77 significant?
SRF (Serum Response Factor) is a ubiquitous nuclear protein that functions as a transcription factor binding to serum response elements (SREs). These SREs are short sequences of dyad symmetry located approximately 300 bp upstream of transcription initiation sites in target genes such as c-fos . SRF plays crucial roles in:
-
Regulation of immediate-early genes
-
Cell cycle control
-
Apoptosis regulation
-
Cell growth and differentiation
-
Cardiac differentiation and maturation
-
Cytoskeletal gene expression
Phosphorylation at Ser77 is a key post-translational modification that regulates SRF activity. This modification affects SRF's ability to interact with cofactors and bind to DNA, thereby influencing downstream gene expression patterns .
What are the typical applications for Phospho-SRF (Ser77) antibody?
The Phospho-SRF (Ser77) antibody has several validated research applications:
The antibody specifically detects endogenous levels of SRF protein only when phosphorylated at serine 77, allowing researchers to study phosphorylation-dependent mechanisms .
How is the Phospho-SRF (Ser77) antibody produced and purified?
The production process involves:
-
Immunizing rabbits with synthetic phosphopeptides conjugated to KLH (Keyhole Limpet Hemocyanin)
-
The phosphopeptide corresponds to the sequence around the phosphorylation site of serine 77 (L-Y-S(p)-G-S) derived from Human SRF
-
Purification through affinity chromatography using epitope-specific phosphopeptides
-
Removal of non-phospho-specific antibodies through chromatography using non-phosphopeptides
This rigorous production and purification strategy ensures high specificity for the phosphorylated form of SRF at Ser77 .
How does phosphorylation at Ser77 affect SRF's interaction with cofactors?
SRF functions through interactions with various cofactors, including:
-
MRTFA (myocardin-related transcription factor A), which controls expression of genes regulating cytoskeleton
-
TCFs (ternary complex factors), which are downstream of MAPK pathways
Phosphorylation at Ser77 affects these interactions by:
-
Altering SRF's conformation, potentially exposing or hiding binding surfaces
-
Modifying the electrostatic properties of the protein-protein interaction interface
-
Creating phosphorylation-dependent binding sites for specific cofactors
The SRF-MRTFA complex activity responds to Rho GTPase-induced changes in cellular globular actin (G-actin) concentration, coupling cytoskeletal gene expression to cytoskeletal dynamics . Phosphorylation at Ser77 may regulate this responsiveness, though more research is needed to fully elucidate these mechanisms.
What signaling pathways regulate SRF Ser77 phosphorylation?
SRF is a downstream target of multiple signaling pathways:
-
MAPK pathway: Activates SRF through phosphorylation, affecting its interaction with ternary complex factors (TCFs)
-
Rho GTPase signaling: Influences SRF-MRTFA complex activity through effects on actin dynamics
-
Calcium signaling: May regulate SRF phosphorylation through calcium-dependent kinases
Serine 77 phosphorylation occurs in response to various stimuli. For example, treatment of Jurkat cells with PMA (phorbol 12-myristate 13-acetate) at 125ng/ml for 30 minutes induces SRF phosphorylation at Ser77, making this an effective positive control for antibody validation studies .
How does SRF phosphorylation relate to MSK1-mediated histone H3 phosphorylation?
Research demonstrates an intricate relationship between transcription factor phosphorylation and chromatin modification:
-
Activators like SRF, Elk-1, CREB, and ATF1 bound to their cognate sites recruit MSK1 to phosphorylate histone H3 at Ser-10 within chromatin
-
This activator-dependent phosphorylation of histone H3 occurs preferentially near promoter regions
-
Among these activators, CREB plays a predominant role in MSK1-mediated phosphorylation of histone H3
The phosphorylation state of SRF at Ser77 may influence its ability to participate in this recruitment process, potentially affecting chromatin remodeling and gene expression .
What are the optimal experimental conditions for detecting phospho-SRF (Ser77)?
For successful detection of phosphorylated SRF (Ser77), researchers should consider:
For Western blot applications, stimulating cells with PMA (125ng/ml for 30 minutes) can serve as a positive control for SRF phosphorylation at Ser77 .
What controls should be included when using Phospho-SRF (Ser77) antibody?
Rigorous experimental design requires appropriate controls:
-
Positive control: Lysates from Jurkat cells treated with PMA (125ng/ml for 30 minutes)
-
Phosphopeptide competition: Treating antibody with the synthetic phosphopeptide should block signal
-
Non-phosphopeptide competition: Should not affect antibody binding
-
Total SRF antibody: To compare phosphorylated vs. total SRF levels
-
Negative control samples: Tissues or cells known not to express SRF
The search results demonstrate validation studies showing signal reduction when phospho-peptide is used for competition, confirming antibody specificity .
How can researchers troubleshoot weak or absent phospho-SRF (Ser77) signal?
Common issues and solutions:
When troubleshooting, always include positive controls (like PMA-treated Jurkat cell extracts) to verify antibody functionality .
How can Phospho-SRF (Ser77) antibody be used to study cardiac development and function?
SRF is required for cardiac differentiation and maturation . Researchers can apply Phospho-SRF (Ser77) antibody to:
-
Track phosphorylation changes during cardiac differentiation of stem cells
-
Compare phosphorylation patterns in normal vs. pathological cardiac tissues
-
Investigate the relationship between SRF phosphorylation and expression of cardiac-specific genes
-
Study the effects of cardiac stress on SRF phosphorylation status
Immunohistochemistry analysis of paraffin-embedded human heart tissue can reveal the distribution and levels of phosphorylated SRF in different cardiac cell types and disease states .
What techniques can be combined with Phospho-SRF (Ser77) antibody for comprehensive functional studies?
Integrative approaches include:
-
ChIP-seq: Determine how Ser77 phosphorylation affects SRF binding to chromatin
-
Co-immunoprecipitation: Investigate how phosphorylation alters protein-protein interactions
-
Proximity ligation assay: Visualize interactions between phospho-SRF and cofactors in situ
-
Phosphorylation site mutations: Compare wild-type SRF with S77A (non-phosphorylatable) and S77D/E (phosphomimetic) mutants
-
Mass spectrometry: Identify additional post-translational modifications co-occurring with Ser77 phosphorylation
Integrating these approaches provides deeper insight into how phosphorylation at this specific residue regulates SRF function across various cellular contexts.
Technical Data Table
This technical data compilation provides researchers with essential information for experimental planning and validation when working with Phospho-SRF (Ser77) antibody.
