TY - JOUR
T1 - Super-resolution microscopy localizes perilipin 5 at lipid droplet-mitochondria interaction sites and at lipid droplets juxtaposing to perilipin 2
AU - Gemmink, Anne
AU - Daemen, Sabine
AU - Kuijpers, Helma J. H.
AU - Schaart, Gert
AU - Duimel, Hans
AU - Lopez-Iglesias, Carmen
AU - van Zandvoort, Marc A. M. J.
AU - Knoops, Kevin
AU - Hesselink, Matthijs K. C.
PY - 2018/11
Y1 - 2018/11
N2 - Objective: Intramyocellular lipid droplets (LD) and their coat proteins PLIN2 and PLIN5 are involved in lipolysis, with a putative role for PLIN5 in mitochondrial tethering. Reportedly, these proteins co-localize and cover the surface of the LD. To provide the spatial basis for understanding how these proteins possess their distinct roles, we examined the precise location of PLIN2 and PLIN5 and explored PLIN5 presence at LD-mitochondria contact sites using Stimulated emission depletion (STED) microscopy and correlative light-electron microscopy (CLEM) in human skeletal muscle sections.Methods: LDs were stained by MDH together with combinations of mitochondria] proteins and PLINs. Subcellular distribution and co-localization of PLIN proteins and mitochondria was imaged by STED microscopy (Leica TCS SP8) and quantified using Pearson's correlation coefficients and intensity profile plots. CLEM was employed to examine the presence of PLIN5 on mitochondria-LD contact sites.Results: Both PLIN2 and PLIN5 localized to the LD in a dot-like, juxtaposed fashion rather than colocalizing and covering the entire LD. Both STED and CLEM revealed a high fraction of PLIN5 at the LD-mitochondria interface, but not at mitochondrial cristae, as suggested previously.Conclusion: Using two super-resolution imaging approaches, this is the first study to show that in sections of human skeletal muscle PLIN2 and PLIN5 localize to the LD at distinct sites, with abundance of PLIN5 at LD-mitochondria tethering sites. This novel spatial information uncovers that PLIN proteins do not serve as lipolytic barriers but rather are docking sites for proteins facilitating selective lipase access under a variety of lipolytic conditions.
AB - Objective: Intramyocellular lipid droplets (LD) and their coat proteins PLIN2 and PLIN5 are involved in lipolysis, with a putative role for PLIN5 in mitochondrial tethering. Reportedly, these proteins co-localize and cover the surface of the LD. To provide the spatial basis for understanding how these proteins possess their distinct roles, we examined the precise location of PLIN2 and PLIN5 and explored PLIN5 presence at LD-mitochondria contact sites using Stimulated emission depletion (STED) microscopy and correlative light-electron microscopy (CLEM) in human skeletal muscle sections.Methods: LDs were stained by MDH together with combinations of mitochondria] proteins and PLINs. Subcellular distribution and co-localization of PLIN proteins and mitochondria was imaged by STED microscopy (Leica TCS SP8) and quantified using Pearson's correlation coefficients and intensity profile plots. CLEM was employed to examine the presence of PLIN5 on mitochondria-LD contact sites.Results: Both PLIN2 and PLIN5 localized to the LD in a dot-like, juxtaposed fashion rather than colocalizing and covering the entire LD. Both STED and CLEM revealed a high fraction of PLIN5 at the LD-mitochondria interface, but not at mitochondrial cristae, as suggested previously.Conclusion: Using two super-resolution imaging approaches, this is the first study to show that in sections of human skeletal muscle PLIN2 and PLIN5 localize to the LD at distinct sites, with abundance of PLIN5 at LD-mitochondria tethering sites. This novel spatial information uncovers that PLIN proteins do not serve as lipolytic barriers but rather are docking sites for proteins facilitating selective lipase access under a variety of lipolytic conditions.
KW - Perilipin 5
KW - Perilipin 2
KW - Lipid droplets
KW - Skeletal muscle
KW - Mitochondria
KW - Super-resolution microscopy
KW - ADIPOSE TRIGLYCERIDE LIPASE
KW - INDUCED INSULIN-RESISTANCE
KW - FLUORESCENCE MICROSCOPY
KW - SKELETAL-MUSCLE
KW - STIMULATED-EMISSION
KW - PROTEIN
KW - RESOLUTION
KW - SENSITIVITY
KW - LIPOLYSIS
KW - DYNAMICS
U2 - 10.1016/j.bbalip.2018.08.016
DO - 10.1016/j.bbalip.2018.08.016
M3 - Article
C2 - 30591149
SN - 1388-1981
VL - 1863
SP - 1423
EP - 1432
JO - Biochimica et Biophysica Acta-Molecular and Cell Biology of Lipids
JF - Biochimica et Biophysica Acta-Molecular and Cell Biology of Lipids
IS - 11
ER -