In addition, it was found that polycystic kidney disease (PKD) gene product polycystin-1 (PC1), which is localized to primary cilia, can regulate bone development and osteoblast function through the regulation of the osteogenic transcription factor Runx2-II, and modulates intracellular calcium-dependent signaling in osteoblasts, and that depletion of intracellular calcium blocks PC1 activation of the Runx2-II P1, demonstrating the importance of the intracellular calcium pathway in PC1-mediated Runx2-II P1 promoter activity in osteoblasts. Here, PKD1 is linked to polycystic kidney disease.