Phosphorylation of paracellin-1 at Ser217 by protein kinase A is essential for localization in tight junctions

• DOI: 10.1242/jcs.02901
• Publication Date: 2006-04-12T01:33:44Z
• Authors: Akira Ikari; Satomi Matsumoto; Hitoshi Harada; Kuniaki Takagi; Hisayoshi Hayashi; Yuichi Suzuki; Masakuni Degawa; Masao Miwa
• Keywords: Adenosine triphosphate; Adenosine monophosphate; Dephosphorylation

Although paracellin-1 (PCLN-1) is known to have a crucial role in the control of Mg2+ reabsorption kidney, molecular pathways involved regulation PCLN-1 not been clarified. We used FLAG-tagged investigate these further, and found that phosphorylated at Ser217 by protein kinase A (PKA) under physiological conditions Madin-Darby canine kidney (MDCK) cells. expression decreased Na+ permeability, resulting decrease transepithelial electrical resistance (TER). By contrast, enhanced transport. PKA inhibitors, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H-89) myristoylated inhibitor 14-22 amide PKI, an adenylate cyclase inhibitor, 2′,5′-dideoxy adenosine (DDA), reduced phosphoserine level PCLN-1. The inhibitory effect DDA was rescued 8-bromoadenosine-3′,5′-cyclic monophosphate (8-Br-cAMP). inhibitors transport TER. Dephosphorylated moved from detergent-insoluble soluble fractions dissociated ZO-1. fusion with glutathione-S-transferase revealed PKA. Phosphorylated localized tight junction (TJ) along ZO-1, whereas dephosphorylated S217A mutant were translocated into lysosome. degradation inhibited chloroquine, specific lysosome inhibitor. Thus, PKA-dependent phosphorylation essential for its localization TJ