TY - JOUR A1 - Donat, Stefan A1 - Lourenco, Marta Sofia Rocha A1 - Paolini, Alessio A1 - Otten, Cecile A1 - Renz, Marc A1 - Abdelilah-Seyfried, Salim T1 - Heg1 and Ccm1/2 proteins control endocardial mechanosensitivity during zebrafish valvulogenesis JF - eLife N2 - Endothelial cells respond to different levels of fluid shear stress through adaptations of their mechanosensitivity. Currently, we lack a good understanding of how this contributes to sculpting of the cardiovascular system. Cerebral cavernous malformation (CCM) is an inherited vascular disease that occurs when a second somatic mutation causes a loss of CCM1/KRIT1, CCM2, or CCM3 proteins. Here, we demonstrate that zebrafish Krit1 regulates the formation of cardiac valves. Expression of heg1, which encodes a binding partner of Krit1, is positively regulated by blood-flow. In turn, Heg1 stabilizes levels of Krit1 protein, and both Heg1 and Krit1 dampen expression levels of klf2a, a major mechanosensitive gene. Conversely, loss of Krit1 results in increased expression of klf2a and notch1b throughout the endocardium and prevents cardiac valve leaflet formation. Hence, the correct balance of blood-flow-dependent induction and Krit1 protein mediated repression of klf2a and notch1b ultimately shapes cardiac valve leaflet morphology. Y1 - 2018 U6 - https://doi.org/10.7554/eLife.28939 SN - 2050-084X VL - 7 PB - eLife Sciences Publications CY - Cambridge ER -