|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | |||||
First published online 24 May 2005
doi: 10.1242/jcs.02401
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Research Article |

1 Department of Anatomy and Molecular Cell Biology, Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa, Nagoya 466-8550, Japan
2 Harima Institute at SPring-8, RIKEN, Mikazuki, Sayo, Hyogo 679-5148, Japan
3 Institute for Enzyme Research, The University of Tokushima, Tokushima 770-8503, Japan
Author for correspondence (e-mail: tfujimot{at}med.nagoya-u.ac.jp)
Accepted 17 March 2005
Lipid droplets (LDs) are organelles that store neutral lipids, but their regulatory mechanism is not well understood. In the present study, we identified Rab18 as an LD component of HepG2 cells by proteomic analysis, and confirmed its localization by immunohistochemistry and western blotting. Wild-type and dominant-active Rab18 localized to LDs but the dominant-negative form did not. Endogenous Rab18 coexisted with adipocyte differentiation-related protein (ADRP) in LDs, but the labeling intensity of the two proteins showed clear reciprocity. Consistent with this observation, overexpression of Rab18 induced a decrease in the amounts of ADRP in LDs in HepG2 and BALB/c 3T3 cells. Furthermore, Rab18 overexpression caused close apposition of LDs to membrane cisternae connected to the rough ER. Two other procedures that decrease ADRP, i.e. RNA interference and brefeldin A treatment, induced the same morphological change, indicating that decrease in ADRP was the cause of the LD-ER apposition. In accordance with similar structures found between ER and other organelles, we propose that the ER membrane apposed to LDs should be named the LD-associated membrane, or LAM. The present results suggested that Rab18 regulates LAM formation, which is likely to be involved in mobilizing lipid esters stored in LDs.
Key words: Lipid droplet, Mass spectrometry, Rab18, Endoplasmic reticulum, Membrane apposition
This article has been cited by other articles:
![]() |
S. Y. Dejgaard, A. Murshid, A. Erman, O. Kizilay, D. Verbich, R. Lodge, K. Dejgaard, T. B. N. Ly-Hartig, R. Pepperkok, J. C. Simpson, et al. Rab18 and Rab43 have key roles in ER-Golgi trafficking J. Cell Sci., August 15, 2008; 121(16): 2768 - 2781. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. A. Reinhardt and J. D. Lippolis Developmental Changes in the Milk Fat Globule Membrane Proteome During the Transition from Colostrum to Milk J Dairy Sci, June 1, 2008; 91(6): 2307 - 2318. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. K. Zehmer, R. Bartz, P. Liu, and R. G. W. Anderson Identification of a novel N-terminal hydrophobic sequence that targets proteins to lipid droplets J. Cell Sci., June 1, 2008; 121(11): 1852 - 1860. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. A. Ducharme and P. E. Bickel Minireview: Lipid Droplets in Lipogenesis and Lipolysis Endocrinology, March 1, 2008; 149(3): 942 - 949. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. L. Listenberger, A. G. Ostermeyer-Fay, E. B. Goldberg, W. J. Brown, and D. A. Brown Adipocyte differentiation-related protein reduces the lipid droplet association of adipose triglyceride lipase and slows triacylglycerol turnover J. Lipid Res., December 1, 2007; 48(12): 2751 - 2761. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. L. Schwartz, C. Cao, O. Pylypenko, A. Rak, and A. Wandinger-Ness Rab GTPases at a glance J. Cell Sci., November 15, 2007; 120(22): 3905 - 3910. [Full Text] [PDF] |
||||
![]() |
S. Boulant, P. Targett-Adams, and J. McLauchlan Disrupting the association of hepatitis C virus core protein with lipid droplets correlates with a loss in production of infectious virus J. Gen. Virol., August 1, 2007; 88(8): 2204 - 2213. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Tsuiki, A. Fujita, Y. Ohsaki, J. Cheng, T. Irie, K. Yoshikawa, H. Senoo, K. Mishima, T. Kitaoka, and T. Fujimoto All-trans-Retinol Generated by Rhodopsin Photobleaching Induces Rapid Recruitment of TIP47 to Lipid Droplets in the Retinal Pigment Epithelium Invest. Ophthalmol. Vis. Sci., June 1, 2007; 48(6): 2858 - 2867. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Fujimoto, H. Itabe, T. Kinoshita, K. J. Homma, J. Onoduka, M. Mori, S. Yamaguchi, M. Makita, Y. Higashi, A. Yamashita, et al. Involvement of ACSL in local synthesis of neutral lipids in cytoplasmic lipid droplets in human hepatocyte HuH7 J. Lipid Res., June 1, 2007; 48(6): 1280 - 1292. [Abstract] [Full Text] [PDF] |
||||
![]() |
H.-C. Wan, R. C. N. Melo, Z. Jin, A. M. Dvorak, and P. F. Weller Roles and origins of leukocyte lipid bodies: proteomic and ultrastructural studies FASEB J, January 1, 2007; 21(1): 167 - 178. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Mannova, R. Fang, H. Wang, B. Deng, M. W. McIntosh, S. M. Hanash, and L. Beretta Modification of Host Lipid Raft Proteome upon Hepatitis C Virus Replication Mol. Cell. Proteomics, December 1, 2006; 5(12): 2319 - 2325. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Sztalryd, M. Bell, X. Lu, P. Mertz, S. Hickenbottom, B. H.-J. Chang, L. Chan, A. R. Kimmel, and C. Londos Functional Compensation for Adipose Differentiation-related Protein (ADFP) by Tip47 in an ADFP Null Embryonic Cell Line J. Biol. Chem., November 10, 2006; 281(45): 34341 - 34348. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Robenek, O. Hofnagel, I. Buers, M. J. Robenek, D. Troyer, and N. J. Severs Adipophilin-enriched domains in the ER membrane are sites of lipid droplet biogenesis J. Cell Sci., October 15, 2006; 119(20): 4215 - 4224. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. T. Browman, M. E. Resek, L. D. Zajchowski, and S. M. Robbins Erlin-1 and erlin-2 are novel members of the prohibitin family of proteins that define lipid-raft-like domains of the ER J. Cell Sci., August 1, 2006; 119(15): 3149 - 3160. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Beller, D. Riedel, L. Jansch, G. Dieterich, J. Wehland, H. Jackle, and R. P. Kuhnlein Characterization of the Drosophila Lipid Droplet Subproteome Mol. Cell. Proteomics, June 1, 2006; 5(6): 1082 - 1094. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Ohsaki, J. Cheng, A. Fujita, T. Tokumoto, and T. Fujimoto Cytoplasmic Lipid Droplets Are Sites of Convergence of Proteasomal and Autophagic Degradation of Apolipoprotein B Mol. Biol. Cell, June 1, 2006; 17(6): 2674 - 2683. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Marcinkiewicz, D. Gauthier, A. Garcia, and D. L. Brasaemle The Phosphorylation of Serine 492 of Perilipin A Directs Lipid Droplet Fragmentation and Dispersion J. Biol. Chem., April 28, 2006; 281(17): 11901 - 11909. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Martin, K. Driessen, S. J. Nixon, M. Zerial, and R. G. Parton Regulated Localization of Rab18 to Lipid Droplets: EFFECTS OF LIPOLYTIC STIMULATION AND INHIBITION OF LIPID DROPLET CATABOLISM J. Biol. Chem., December 23, 2005; 280(51): 42325 - 42335. [Abstract] [Full Text] [PDF] |
||||