抄録
Production of inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG) by phospholipase C is critical in lymphocyte activation. In contrast to store-operated Ca2+ entry activated by IP3-induced Ca2+ release from ER Ca2+ stores, importance of DAG-activated Ca2+ entry pathways remains elusive. Here, we describe the physiological role of DAG-activated Ca2+ entry in B cell receptor (BCR) signaling using TRPC3-deficient avian DT40 B lymphocytes. They showed significant impairment of DAG-activated cation currents but an intact SOC activity. TRPC3 deficiency suppressed the sustained translocation of protein kinase C (PKC)β to the plasma membrane (PM) and PKC-dependent ERK activation upon BCR stimulation. Since TRPC3 directly associated with PKCβ in a Ca2+ entry-dependent manner, TRPC3 functions as both a Ca2+-entry channel and a molecular anchor for PM translocation of PKCβ. [J Physiol Sci. 2008;58 Suppl:S26]
