Downstream signal transduction Pathway R-HSA-186763

Platelet-derived growth factors (PDGFs) are secreted ligands that activate PDGF receptor tyrosine kinases to control cell proliferation, migration, survival, and differentiation. The Reactome pathway R-HSA-186763, Downstream signal transduction, captures the molecular events that occur after PDGF receptor autophosphorylation, when phosphorylated tyrosine residues on PDGFRA and PDGFRB serve as docking sites for SH2-domain-containing proteins. This pathway is central to understanding how extracellular growth factor cues are converted into intracellular biochemical signals. The pathway includes both enzymatic effectors and non-enzymatic adaptors. Enzymes such as phosphatidylinositol 3-kinase (PI3K), phospholipase C gamma (PLCG1), SRC-family kinases, the tyrosine phosphatase PTPN11 (SHP2), and the Ras GTPase-activating protein RASA1 are recruited or activated at the receptor. Adaptor proteins such as GRB2, NCK1, NCK2, CRK, CRKL, and BCAR1 link the receptor to downstream catalytic molecules, including the SOS1-RAS module and cytoskeletal regulators. Because these events are frequently altered in cancer and other diseases, R-HSA-186763 is a high-value framework for experimental studies of signal transduction. For researchers, this pathway provides a structured map of PDGF-dependent signaling nodes that can be perturbed with CRISPR-based models and measured with phosphoproteomics, transcriptomics, and functional assays. The sections below summarize the pathway, its key genes, disease relevance, and practical research strategies. What Is the Downstream signal transduction Pathway? R-HSA-186763 is the Reactome pathway that describes the intracellular signaling events triggered when autophosphorylated PDGF receptors recruit and activate downstream molecules containing SH2 domains. In this pathway, phosphorylated tyrosine residues on PDGFRA and PDGFRB act as docking sites for enzymes such as PI3K, PLCG1, SRC-family kinases, PTPN11, and RASA1, as well as adaptor proteins such as GRB2, NCK1, NCK2, CRK, CRKL, and BCAR1. Binding or receptor-mediated phosphorylation activates these downstream molecules, which then propagate signals through RAS-MAPK, PI3K-AKT, phospholipase C, STAT, and cytoskeletal regulatory modules.

R-HSA-186763 is the Reactome pathway that describes the intracellular signaling events triggered when autophosphorylated PDGF receptors recruit and activate downstream molecules containing SH2 domains. In this pathway, phosphorylated tyrosine residues on PDGFRA and PDGFRB act as docking sites for enzymes such as PI3K, PLCG1, SRC-family kinases, PTPN11, and RASA1, as well as adaptor proteins such as GRB2, NCK1, NCK2, CRK, CRKL, and BCAR1. Binding or receptor-mediated phosphorylation activates these downstream molecules, which then propagate signals through RAS-MAPK, PI3K-AKT, phospholipase C, STAT, and cytoskeletal regulatory modules.

R-HSA-186763 is important because it defines the molecular logic by which PDGF receptor activation is translated into diverse cellular outcomes, including proliferation, survival, migration, and differentiation. Many of its components are proto-oncogenes, tumor suppressors, or signaling hubs whose dysregulation contributes to cancer, fibrosis, and developmental disorders. Understanding this pathway at the level of individual genes and phosphosites supports target discovery, biomarker development, and rational design of combination therapies.

The following table summarizes representative genes in R-HSA-186763 and their major roles and research relevance.

R-HSA-186763 is regulated by multiple feedback and crosstalk mechanisms. Receptor autophosphorylation is counteracted by protein tyrosine phosphatases, including PTPN11, which can both promote and attenuate RAS-ERK signaling depending on context. RASA1 acts as a GTPase-activating protein that hydrolyzes GTP on RAS, thereby terminating RAS-dependent signals. PI3K signaling is opposed by lipid phosphatases such as PTEN, although PTEN is not listed in this pathway. Adaptor proteins such as GRB2, NCK1, NCK2, CRK, and CRKL can compete for phosphotyrosine sites and modulate signal duration and specificity. Crosstalk with other receptor tyrosine kinase pathways and integrin signaling further shapes the output of PDGF receptor activation.

Dysregulated PDGF signaling is implicated in multiple cancers, including glioblastoma, gastrointestinal stromal tumors, and leukemias. Activating mutations or overexpression of PDGFRA, PDGFRB, PIK3CA, KRAS, NRAS, HRAS, and SRC can drive proliferation and survival. Components of R-HSA-186763 are therefore studied as oncogenic drivers and therapeutic targets.

PDGF signaling promotes fibroblast proliferation and extracellular matrix deposition, contributing to fibrosis in lung, liver, and kidney. Vascular smooth muscle cell proliferation and migration downstream of PDGF receptors are also important in atherosclerosis and restenosis. Genes such as PDGFRA, PDGFRB, and PLCG1 are relevant to these processes.

Germline mutations in PDGFRA, PDGFRB, and PTPN11 are associated with developmental syndromes, including some craniofacial and skeletal disorders. The SH2-domain-mediated signaling events described in R-HSA-186763 are critical for normal development.

STAT transcription factors, including STAT1, STAT3, STAT5A, STAT5B, and STAT6, are activated downstream of PDGF receptors and contribute to immune and inflammatory gene expression programs. This links R-HSA-186763 to cytokine-like signaling outputs in the tumor microenvironment.

RNA-seq can measure changes in gene expression after PDGF stimulation or CRISPR perturbation of pathway genes. This helps identify transcriptional outputs downstream of STAT and other transcription factors in R-HSA-186763.

Mass spectrometry-based phosphoproteomics can quantify phosphorylation events on PDGF receptors and downstream effectors. This provides a global view of signaling dynamics and can reveal feedback and crosstalk mechanisms.

Luciferase or fluorescent reporters driven by STAT, AP-1, or other pathway-responsive promoters can measure pathway activity. These assays are useful for dose-response and time-course experiments.

Fluorescence microscopy of tagged proteins can visualize recruitment of SH2-domain proteins to activated receptors and changes in cell morphology. Live-cell imaging can track signaling dynamics and cytoskeletal rearrangements.

EDITGENE provides specialized CRISPR cell model and screening services to help researchers dissect R-HSA-186763 and related signaling pathways with rigor and reproducibility.

R-HSA-186763 provides a comprehensive map of the signaling events that occur downstream of PDGF receptor activation, from SH2-domain-mediated recruitment to activation of PI3K, PLCG1, SRC, PTPN11, RAS, STAT, and cytoskeletal adaptors. Understanding this pathway is essential for cancer biology, fibrosis research, and developmental studies. CRISPR-based cell models and multi-omics methods now allow precise perturbation and measurement of each node in this pathway. EDITGENE supports these efforts with custom knockout, point-mutation, knock-in, overexpression, and screening services tailored to PDGF signaling research.