Endoplasmic Reticulum Protein 44 Mediates Cell Migration

Abstract

ABSTRACTCell motility plays a fundamental role in cancer metastasis. But the intracellular signaling mechanism that regulates cell motility remains unclarified. We have studied the functional role of intracellular Ca2+ release channel IP3 receptors(IP3Rs) and their novel negatively regulatory protein endoplasmic reticulum protein 44 (ERp44) in A549 cell migration. In wound healing assay, 30 μM 2-APB was used to inhibit Ca2+ release through the IP3Rs, and significantly decreased cell migration rates; while 20 μM Ryanodine did show any effect on cell migration. Immunofluorescence assay showed that cell polarization, membrane protrusion and formation of stress fiber of 2-APB treated A549 cells were inhibited 2h after wound producing. Consistent with this finding, the time-lapse imaging showed A549 cell became less motile after 2-APB treatment. Over expression of ERp44 in A549 cells inhibited 10 μM eATP-induced calcium activates and cell polarization, consequently inhibited cell migration both in wound healing assay and the time-lapse imaging. However, over expression of ERp44 in rat vascular smooth muscle, in which IP3Rs were not required for cell migration, did not inhibit cell polarization and cell migration. These findings suggest that IP3Rs are required for A549 cell migration and over expression of ERp44 inhibits cell polarization and cell migration through negatively regulating IP3Rs.Key Words Cell migration; ERp44; IP3Rs