Open AccessSpatiotemporal dynamics of triglyceride storage in unilocular adipocytes
Author(s) -
Michael P. Chu,
Harini Sampath,
David Y. Cahana,
Christoph Kahl,
Romel Somwar,
Anda Cornea,
Charles T. Roberts,
Oleg Varlamov
Publication year - 2014
Publication title -
molecular biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.463
H-Index - 225
eISSN - 1939-4586
pISSN - 1059-1524
DOI - 10.1091/mbc.e14-06-1085
Subject(s) - lipid droplet , endoplasmic reticulum , biology , organelle , microbiology and biotechnology , cytoplasm , adipocyte , adipose tissue , lipid metabolism , perilipin , mitochondrion , biophysics , biochemistry
The spatiotemporal dynamics of triglyceride (TG) storage in unilocular adipocytes are not well understood. Here we applied ex vivo technology to study trafficking and metabolism of fluorescent fatty acids in adipose tissue explants. Live imaging revealed multiple cytoplasmic nodules surrounding the large central lipid droplet (cLD) of unilocular adipocytes. Each cytoplasmic nodule harbors a series of closely associated cellular organelles, including micro–lipid droplets (mLDs), mitochondria, and the endoplasmic reticulum. Exogenously added free fatty acids are rapidly adsorbed by mLDs and concurrently get esterified to TG. This process is greatly accelerated by insulin. mLDs transfer their content to the cLD, serving as intermediates that mediate packaging of newly synthesized TG in the large interior of a unilocular adipocyte. This study reveals novel cell biological features that may contribute to the mechanism of adipocyte hypertrophy.