GSN and heart disorder: To test the role of gelsolin in mediating heart disease in the setting of reduced PI3Kα function, we next generated double-mutant mice by intercrossing the dominant-negative PI3Kα (PI3KαDN) mice with GSNKO mice, generating PI3Kα dominant-negative GSNKO double-mutant (PI3KαDN/GSNKO) mice (Supplementary Fig. 2b).