Vitamin K2-Dependent GGCX and MGP Are Required for Homeostatic Calcium Regulation of Sperm Maturation

？ Epididymal sperm maturation requires VK2-dependent GGCX-mediated MGP carboxylation ？ A GGCX SNP mutation is found in infertile men suffering from asthenozoospermia ？ Carboxylated-MGP regulates intercellular calcium signaling in the epididymal lumen ？ Calcium-regulated MGP binds to proteins in a biphasic-manner and favors low level