PDGFRα

PDGFRα
Name	Platelet-derived growth factor receptor alpha
Other names	CD140a
Organism	Human
Gene id	5156
Location	Chromosome 4q12
Type	Receptor tyrosine kinase

PDGFRα is a receptor tyrosine kinase encoded by the human PDGFRA gene, involved in cell proliferation, migration, and survival. It is expressed in mesenchymal lineage cells and plays critical roles in embryogenesis, tissue repair, and stromal interactions. Abnormal activity is implicated in various cancers and fibrotic diseases, making it a therapeutic target for small molecules and biologics.

Structure and Expression

The protein is a single-pass transmembrane receptor composed of an extracellular ligand-binding region with five immunoglobulin-like domains, a transmembrane helix, a juxtamembrane segment, and an intracellular tyrosine kinase domain; the gene resides at Chromosome 4 (human), locus 4q12, near KIT (gene) and KDR (gene). Expression is prominent in mesenchymal populations such as fibroblasts, pericytes, and certain neural crest derivatives during embryogenesis described in studies from groups at Harvard University, Massachusetts Institute of Technology, and the Max Planck Society. Tissue-specific distribution includes stromal compartments of the lung, heart, and gastrointestinal tract, with reported modulation by transcription factors including SOX9, FOXC2, and EGR1 in experiments performed at Johns Hopkins University and Stanford University. Alternative splicing and post-translational glycosylation generate isoforms characterized in cohorts from National Institutes of Health and European Molecular Biology Laboratory.

Function and Signaling Pathways

Activation triggers autophosphorylation on intracellular tyrosine residues that recruit SH2-domain-containing adapters such as PI3K regulatory subunits and GRB2, initiating downstream cascades like the PI3K–AKT pathway, RAS–MAPK pathway, and PLCγ-mediated signaling; these pathways are also central to signaling studied at Cold Spring Harbor Laboratory and the Salk Institute. Cross-talk occurs with other receptor tyrosine kinases including EGFR and MET, and with integrin-mediated adhesion complexes analyzed by teams at Imperial College London and University of Cambridge. Signaling regulates cytoskeletal dynamics through Rho-family GTPases characterized in work from University of California, San Francisco and controls transcriptional programs involving MYC and HIF1A that link to proliferation and hypoxic responses documented by researchers at University of Oxford and UCLA.

Ligands and Receptor Activation

Natural ligands comprise platelet-derived growth factor isoforms PDGF-AA, PDGF-AB, and PDGF-BB, produced by cell types such as platelets, macrophages, and endothelial cells; ligand biology has been elucidated in studies at Weill Cornell Medicine and Yale University. Ligand binding promotes dimerization (homodimers or heterodimers) and trans-autophosphorylation in mechanisms paralleled in structural studies from European Synchrotron Radiation Facility and Rutherford Appleton Laboratory. Co-receptors and modifiers including Syndecan-4 and heparan sulfate proteoglycans modulate affinity and gradient formation as shown in collaborations with Karolinska Institutet and McGill University. Mutations that alter ligand-independent activation were first noted in clinical reports from Mayo Clinic and molecular analyses at Dana-Farber Cancer Institute.

Role in Development and Physiology

During embryonic development PDGFRα-dependent signaling drives proliferation and migration of mesenchymal progenitors contributing to craniofacial structures, cardiac outflow tract, and limb morphogenesis described in landmark work at Columbia University and University of Pennsylvania. In organogenesis, roles include alveolar myofibroblast differentiation in lung maturation and regulation of interstitial fibroblasts in kidney development, with findings from University of Toronto and University of Washington. Physiologically, the receptor participates in wound healing and angiogenesis, coordinating with endothelial cells and pericytes studied in translational programs at Mayo Clinic, Cleveland Clinic, and Karolinska Institutet.

Involvement in Disease and Oncogenesis

Constitutive activation contributes to oncogenesis in gastrointestinal stromal tumors first linked by investigations at Memorial Sloan Kettering Cancer Center and M.D. Anderson Cancer Center, and in myeloid malignancies reported by groups at Fred Hutchinson Cancer Center and University of Texas Southwestern Medical Center. Amplifications and point mutations correlate with aggressive phenotypes in gliomas, sarcomas, and melanoma cohorts analyzed at Johns Hopkins University and Institut Curie. Aberrant signaling also promotes organ fibrosis in pulmonary fibrosis and systemic sclerosis described in clinical series from National Heart, Lung, and Blood Institute and European Respiratory Society. Resistance mechanisms to targeted therapies involve secondary mutations and pathway reactivation reported by investigators at Vanderbilt University and Karolinska Institutet.

Therapeutic Targeting and Inhibitors

Small-molecule tyrosine kinase inhibitors such as imatinib, sunitinib, and crenolanib have been developed and trialed in settings at Pfizer, Novartis, and academic consortia including European Organisation for Research and Treatment of Cancer; clinical responses vary with mutation type as documented in trials run by National Cancer Institute. Monoclonal antibodies and ligand traps targeting PDGF ligands or extracellular domains have been explored in preclinical programs at Genentech and Roche. Combination strategies pairing kinase inhibitors with agents against VEGF signaling, immune checkpoints investigated at Memorial Sloan Kettering Cancer Center and MD Anderson, or downstream effectors like mTOR from studies at Baylor College of Medicine aim to overcome resistance. Ongoing biomarker development and next-generation inhibitors come from collaborations among Broad Institute, European Molecular Biology Laboratory, and clinical networks including ASCO-linked cooperative groups.

Category:Receptor tyrosine kinases