PI3Kβ

PI3Kβ is a class I PI3K catalytic isoform that produces PIP₃, linking receptor inputs to signaling networks that regulate cell growth, survival, and movement^[1]. Mechanistically, PI3Kβ uniquely supports synergistic PIP₃ formation when GPCR and RTK pathways are coactivated in myeloid cells, whereas p110α, p110β, and p110δ show partial redundancy downstream of M-CSF alone and p110γ acts nonredundantly downstream of C5a alone^[1]. In PTEN-deficient breast tumour models, PI3Kβ inactivation reduced STAT3 signaling, increased immune-stimulatory molecules, and promoted anti-tumour immune responses^[2]. Compared with related PI3K isoforms, this evidence positions PI3Kβ as a context-specific integrator of coincident receptor signaling and a disease-relevant driver in PTEN-null tumours^[1][2]. For experimental applications, the PI3Kβ-selective inhibitor KIN-193 blocked AKT signaling and tumour growth dependent on p110β activation or PTEN loss, while pharmacological PI3Kβ inhibition also synergized with immunotherapy in PTEN-null breast tumour models^[3][2].