HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 277, Issue 38, 34826-34835, September 20, 2002

This Article Full Text Full Text (PDF) All Versions of this Article: 277/38/34826    most recent M205028200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Larsen, A.-K. R. Articles by Seglen, P. O. Search for Related Content PubMed PubMed Citation Articles by Larsen, A.-K. R. Articles by Seglen, P. O. Social Bookmarking                      What's this?

Naringin-sensitive Phosphorylation of Plectin, a Cytoskeletal Cross-linking Protein, in Isolated Rat Hepatocytes^*

Ann-Kristin Ruud Larsen^§, Michael T. N. Møller^§, Henrietta Blankson, Hamid R. Samari, Lise Holden, and Per O. Seglen

From the Proteomics and Mammalian Cell Biology Section, Department of Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway

To identify phosphoproteins that might play a role in naringin-sensitive hepatocellular cytoskeletal disruption and apoptosis induced by algal toxins, hepatocyte extracts were separated by gel electrophoresis and immunostained with a phosphothreonine-directed antibody. Use of dilute (5%) polyacrylamide gels containing 6 M urea allowed the resolution of one very large (~500-kDa) okadaic acid- and naringin-sensitive phosphoprotein, identified by tryptic fingerprinting, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and immunostaining as the cytolinker protein, plectin. The naringin-sensitive phosphorylation induced by okadaic acid and microcystin-LR probably reflected inhibition of a type 2A protein phosphatase, whereas the naringin-resistant phosphorylation induced by calyculin A, tautomycin, and cantharidin probably involved a type 1 phosphatase. Okadaic acid caused a collapse of the plectin-immunostaining bile canalicular sheaths and the general cytoskeletal plectin network into numerous medium-sized plectin aggregates. Inhibitors of protein kinase C, cAMP-dependent protein kinase, or Ca²⁺/calmodulin-dependent kinase II had moderate or no protective effects on plectin network disruption, whereas naringin offered 86% protection. Okadaic acid induced a naringin-sensitive phosphorylation of AMP-activated protein kinase (AMPK), the stress-activated protein kinases SEK1 and JNK, and S6 kinase. The AMPK-activating kinase (AMPKK) is likely to be the target of inhibition by naringin, the other kinases serving as downstream components of an AMPKK-initiated signaling pathway.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				E. Ansorena, C. Berasain, M. J. L. Zabalza, M. A. Avila, E. R. Garcia-Trevijano, and M. J. Iraburu Differential regulation of the JNK/AP-1 pathway by S-adenosylmethionine and methylthioadenosine in primary rat hepatocytes versus HuH7 hepatoma cells Am J Physiol Gastrointest Liver Physiol, June 1, 2006; 290(6): G1186 - G1193. [Abstract] [Full Text] [PDF]

				M. Gregor, A. Zeold, S. Oehler, K. A. Marobela, P. Fuchs, G. Weigel, D. G. Hardie, and G. Wiche Plectin scaffolds recruit energy-controlling AMP-activated protein kinase (AMPK) in differentiated myofibres J. Cell Sci., May 1, 2006; 119(9): 1864 - 1875. [Abstract] [Full Text] [PDF]

				M. Zubare-Samuelov, M. E. Shaul, I. Peri, A. Aliluiko, O. Tirosh, and M. Naim Inhibition of signal termination-related kinases by membrane-permeant bitter and sweet tastants: potential role in taste signal termination Am J Physiol Cell Physiol, August 1, 2005; 289(2): C483 - C492. [Abstract] [Full Text] [PDF]

				A. K. Reiter, D. R. Bolster, S. J. Crozier, S. R. Kimball, and L. S. Jefferson Repression of protein synthesis and mTOR signaling in rat liver mediated by the AMPK activator aminoimidazole carboxamide ribonucleoside Am J Physiol Endocrinol Metab, May 1, 2005; 288(5): E980 - E988. [Abstract] [Full Text] [PDF]

				M. T.N. Moller, H. R. Samari, and P. O. Seglen Toxin-Induced Tail Phosphorylation of Hepatocellular S6 Kinase: Evidence for a Dual Involvement of the AMP-Activated Protein Kinase in S6 Kinase Regulation Toxicol. Sci., December 1, 2004; 82(2): 628 - 637. [Abstract] [Full Text] [PDF]

				A. J. Meijer Amino Acids as Regulators and Components of Nonproteinogenic Pathways J. Nutr., June 1, 2003; 133(6): 2057S - 2062. [Abstract] [Full Text] [PDF]