title: Involvement of myristoylated alanine-rich C kinase substrate phosphorylation and translocation in cholecystokinin-induced amylase release in rat pancreatic acini.
abstract: Cholecystokinin (CCK) is a gastrointestinal hormone that induces exocytotic amylase release in pancreatic acinar cells. The activation of protein kinase C (PKC) is involved in the CCK-induced pancreatic amylase release. Myristoylated alanine-rich C kinase substrate (MARCKS) is a ubiquitously expressed substrate of PKC. MARCKS has been implicated in membrane trafficking in several cell types. The phosphorylation of MARCKS by PKC results in the translocation of MARCKS from the membrane to the cytosol. Here, we studied the involvement of MARCKS in the CCK-induced amylase release in rat pancreatic acini. Employing Western blotting, we detected MARCKS protein in the rat pancreatic acini. CCK induced MARCKS phosphorylation. A PKC-δ inhibitor, rottlerin, inhibited the CCK-induced MARCKS phosphorylation and amylase release. In the translocation assay, we also observed CCK-induced PKC-δ activation. An immunohistochemistry study showed that CCK induced MARCKS translocation from the membrane to the cytosol. When acini were lysed by a detergent, Triton X-100, CCK partially induced displacement of the MARCKS from the GM1a-rich detergent-resistant membrane fractions (DRMs) in which Syntaxin2 is distributed. A MARCKS-related peptide inhibited the CCK-induced amylase release. These findings suggest that MARCKS phosphorylation by PKC-δ and then MARCKS translocation from the GM1a-rich DRMs to the cytosol are involved in the CCK-induced amylase release in pancreatic acinar cells.
authors.affiliation: Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi, Japan; k-satoh@dokkyomed.ac.jp.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Satoh
authors.affiliation: Laboratory of Veterinary Biochemistry, Nihon University College of Bioresource Sciences, Kanagawa, Japan;
authors.forename: Takanori
authors.initials: T
authors.lastname: Narita
authors.affiliation: Department of Physiology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Katsumata-Kato
authors.affiliation: Laboratory of Veterinary Biochemistry, Nihon University College of Bioresource Sciences, Kanagawa, Japan;
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugiya
authors.affiliation: Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi, Japan;
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Seo
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002766:Cholecystokinin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D021962:Membrane Microdomains / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta / Q000187:drug effects / Q000378:metabolism; D050765:Qa-SNARE Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014178:Translocation, Genetic
chemical_list: D000098:Acetophenones; D001578:Benzopyrans; D047908:Intracellular Signaling Peptides and Proteins; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D002766:Cholecystokinin; C085746:rottlerin; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D000681:Amylases
keywords: PKC-δ; Syntaxin2; exocytosis; lipid raft; phosphorylation