PRRG2 (proline-rich Gla domain 2) is a vitamin K-dependent, cell-surface transmembrane protein essential for calcium homeostasis and hemostasis 1. The protein undergoes gamma-glutamyl carboxylation in a vitamin K-dependent manner and is predominantly localized to the cell surface with its Gla domain exposed extracellularly 1. PRRG2 contains tandem PY motifs that mediate binding to the transcriptional coactivator Yes-associated protein (YAP), suggesting involvement in signal transduction 1. Beyond its classical coagulation role, PRRG2 functions as a tumor suppressor in lung cancer pathogenesis. Transcriptional repression of PRRG2 by the oncoprotein ZBTB11 promotes YAP1 activation and lung cancer metastasis 2. PRRG2 belongs to a family of proline-rich Gla proteins with WW binding motifs that interact with numerous cytosolic proteins involved in diverse physiologic processes 3. Warfarin, a widely used anticoagulant that inhibits vitamin K-dependent carboxylation, may impair PRRG2-mediated signaling as an unintended consequence 1. These findings indicate PRRG2 functions beyond hemostasis, with emerging roles in cancer metastasis suppression and YAP-mediated cellular signaling.