Proto-oncogene tyrosine-protein kinase Src–Ras homolog family member A signaling axis (Src–RhoA axis)

The Src–RhoA signaling axis is a critical regulatory pathway involving the non-receptor tyrosine kinase Src and the small GTPase Ras homolog family member A (RhoA). Src modulates RhoA activity primarily by phosphorylating Rho-specific guanine nucleotide exchange factors (GEFs), such as Vav2 and Ephexin, which facilitate the transition of RhoA to its active GTP-bound state [1: PubMed 15103325]. This axis plays a fundamental role in controlling the actin cytoskeleton, focal adhesion dynamics, and cell motility, making it a central driver of cancer cell invasion and metastasis [2: PubMed 29760434]. In addition to oncology, the Src–RhoA pathway is implicated in vascular smooth muscle contraction and the pathogenesis of hypertension [3: PubMed 16373487]. Therapeutic targeting of this axis typically involves Src inhibitors like dasatinib or downstream Rho-associated kinase (ROCK) inhibitors like fasudil [4: PubChem CID 10635]. While effective in preclinical models for reducing metastasis and vascular resistance, clinical challenges include the ubiquitous nature of these proteins and the potential for significant side effects such as pleural effusion and hematologic toxicities [5: PubMed 25622015]. The axis serves as a complex signaling node where multiple upstream inputs converge to regulate cellular architecture and movement. Consequently, monitoring the phosphorylation status of Src and the activation levels of RhoA provides valuable biomarkers for assessing the efficacy of targeted therapies in this pathway [6: PubMed 18483241].

Other names

Src-RhoA pathwaySrc/RhoA signalingSrc-mediated RhoA activation

Inhibition of Src kinase activity prevents the phosphorylation and activation of Rho-guanine nucleotide exchange factors (GEFs), thereby reducing the levels of active GTP-bound RhoA and inhibiting downstream cytoskeletal reorganization.