Mechanism of Action
Plinabulin displays multiple mechanisms mediated by GEF-H1
As a differentiated, brain penetrant microtubule-targeting agent, plinabulin binds beta-tubulin with a fast-off rate (La Sala 2019). Disrupted microtubule polymerization subsequently activates GEF-H1 (guanine-nucleotide-exchange-factor H1), a Rho-GTPase signaling protein sequestered by the C1 domain in an inactive state and activated upon release but in a highly regulated, spatiotemporally dependent manner (Choi 2026; Mitchison 2025).
As a GEF-H1 agonist, plinabulin displays multiple controlled mechanisms:
- Activates the JNK (c-Jun N-terminal kinase) MAPK pathway through RhoA/ROCK signaling leading to DC maturation/M1-like polarization and T-cell activation, as validated in preclinical and clinical studies (Kashyap 2019; Natoli 2021; Lin 2025)
- Promotes HSPC proliferation with bias toward the GMP lineage during GEF-H1 dependent productive hematopoiesis (Chan 2021), contributing to its CIN prevention benefit (Tonra 2020; Blayney 2020)
- Modulates tumor vasculature (Mita 2010) likely through GEF-H1’s association with tight junctions and pericyte phenotypic switching (He 2025; Risinger 2025)