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

This Article Full Text Full Text (PDF) 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Laitinen, S. Articles by Olkkonen, V. M. Search for Related Content PubMed PubMed Citation Articles by Laitinen, S. Articles by Olkkonen, V. M. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol. 43, 245-255, February 2002
Copyright © 2002 by Lipid Research, Inc.

ORP2, a homolog of oxysterol binding protein, regulates cellular cholesterol metabolism

Correspondence to: Vesa M. Olkkonen, To whom correspondence should be addressed., vesa.olkkonen{at}ktl.fi (E-mail)

Oxysterol binding protein (OSBP) related proteins (ORPs) constitute a family that has at least 12 members in humans. In the present study we characterize one of the novel OSBP homologs, ORP2, which we show to be expressed ubiquitously in mammalian tissues. The ORP2 cDNA encodes a deduced 55 kDa protein that lacks a pleckstrin homology (PH) domain, a feature found in the other family members. Sucrose gradient centrifugation analysis of Chinese hamster ovary (CHO) cell post-nuclear supernatant demonstrated that ORP2 is distributed in soluble and membrane-bound fractions. Immunofluorescence microscopy of the endogenous and overexpressed ORP2 in CHO cells suggested that the membrane-bound fraction of the protein localizes to the Golgi apparatus. Stably transfected CHO cells that overexpress ORP2 showed an increase in [¹⁴C]cholesterol efflux to serum, apolipoprotein A-I (apoA-I), and phosphatidyl choline vesicles. The proportion of cellular [¹⁴C]cholesterol that is esterified and the ACAT activity measured as [¹⁴C]oleyl-CoA conversion into cholesteryl [¹⁴C]oleate by the cellular membranes, were markedly decreased in the ORP2 expressing cells. Transient high level overexpression of ORP2 interfered with the clearance of a secretory pathway protein marker from the Golgi complex.

The results implicate ORP2 as a novel regulator of cellular sterol homeostasis and intracellular membrane trafficking. — Laitinen, S., M. Lehto, S. Lehtonen, K. Hyvärinen, S. Heino, E. Lehtonen, C. Ehnholm, E. Ikonen, and V. M. Olkkonen. ORP2, a homolog of oxysterol binding protein, regulates cellular cholesterol metabolism. J. Lipid Res. 2002. 43: 245–255.

Supplementary key words: cholesterol efflux, cholesterol esterification, Golgi apparatus, mRNA expression, protein expression, membrane trafficking

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				R. Hynynen, M. Suchanek, J. Spandl, N. Back, C. Thiele, and V. M. Olkkonen OSBP-related protein 2 is a sterol receptor on lipid droplets that regulates the metabolism of neutral lipids J. Lipid Res., July 1, 2009; 50(7): 1305 - 1315. [Abstract] [Full Text] [PDF]

				K. Bowden and N. D. Ridgway OSBP Negatively Regulates ABCA1 Protein Stability J. Biol. Chem., June 27, 2008; 283(26): 18210 - 18217. [Abstract] [Full Text] [PDF]

				P. P.L. Lam, K. Hyvarinen, M. Kauppi, L. Cosen-Binker, S. Laitinen, S. Keranen, H. Y. Gaisano, and V. M. Olkkonen A Cytosolic Splice Variant of Cab45 Interacts with Munc18b and Impacts on Amylase Secretion by Pancreatic Acini Mol. Biol. Cell, July 1, 2007; 18(7): 2473 - 2480. [Abstract] [Full Text] [PDF]

				R. J. Perry and N. D. Ridgway Oxysterol-binding Protein and Vesicle-associated Membrane Protein-associated Protein Are Required for Sterol-dependent Activation of the Ceramide Transport Protein Mol. Biol. Cell, June 1, 2006; 17(6): 2604 - 2616. [Abstract] [Full Text] [PDF]

				A.-L. Mutka, S. Lusa, M. D. Linder, E. Jokitalo, O. Kopra, M. Jauhiainen, and E. Ikonen Secretion of Sterols and the NPC2 Protein from Primary Astrocytes J. Biol. Chem., November 19, 2004; 279(47): 48654 - 48662. [Abstract] [Full Text] [PDF]

				J. Silva, A. Beckedorf, and E. Bieberich Osteoblast-derived Oxysterol Is a Migration-inducing Factor for Human Breast Cancer Cells J. Biol. Chem., July 3, 2003; 278(28): 25376 - 25385. [Abstract] [Full Text] [PDF]

				M. Johansson, V. Bocher, M. Lehto, G. Chinetti, E. Kuismanen, C. Ehnholm, B. Staels, and V. M. Olkkonen The Two Variants of Oxysterol Binding Protein-related Protein-1 Display Different Tissue Expression Patterns, Have Different Intracellular Localization, and Are Functionally Distinct Mol. Biol. Cell, March 1, 2003; 14(3): 903 - 915. [Abstract] [Full Text] [PDF]