Electron micrographs showing the association of vimentin filaments with the forming of LDs after brief AIM stimulation of human preadipocytes.
(a) Grazing section of two very small LDs (approx. 200 nm in diameter) surrounded by numerous vimentin IF bundles of the “wide-spacing type” with approximately 30–50 nm spacing distance (cp.) and with interconnection of LDs by filaments (arrows). (b) Similar small LDs associated with filaments as seen in (a). (c) Survey electron micrograph showing ordered arrays of vimentin bundles at the surface of LDs. Some LDs can be seen interconnected by IFs (arrows). First evidences of specific assembly of smooth ER tubules forming cisternae sheaths and layers can be noticed (brown-colored system of tubules). Note, at this stage of adipocyte differentiation mitochondria (M) are not directly associated to these forming small LDs. Bars: 0.50 µm.