Biology subjects

Pasolli, H. A.

Publications and source records attributed to Pasolli, H. A..

21 records · Page 2Linked to original sources

bioRxiv2019

Correlative three-dimensional super-resolution and block face electron microscopy of whole vitreously frozen cells

Living cells function through the spatial compartmentalization of thousands of distinct proteins serving a multitude of diverse biochemical needs. Correlative super-resolution (SR) fluorescence and electron microscopy (EM) has emerged as a pathway to directly view nanoscale protein relationships to the underlying global ultrastructure, but has traditionally suffered from tradeoffs of structure preservation, fluorescence retention, resolution, and field of view. We developed a platform for three-dimensional correlative cryogenic SR and focused ion beam milled block-face EM across entire vitreously frozen cells that addresses these issues by preserving native ultrastructure and enabling independent SR and EM workflow optimization. Application to a variety of biological systems revealed a number of unexpected protein-ultrastructure relationships and underscored the value of a comprehensive multimodal view of ultrastructural variability across whole cells.

cell biology↗

bioRxiv2019

Spastin tethers lipid droplets to peroxisomes and directs fatty acid trafficking through ESCRT-III

Lipid droplets (LDs) are neutral lipid storage organelles that transfer lipids to various organelles including peroxisomes. Here, we show that the hereditary spastic paraplegia protein M1 Spastin, a membrane-bound AAA ATPase found on LDs, coordinates fatty acid (FA) trafficking from LDs to peroxisomes through two inter-related mechanisms. First, M1 Spastin forms a tethering complex with peroxisomal ABCD1 to promote LD-peroxisome contact formation. Second, M1 Spastin recruits the membrane-shaping ESCRT-III proteins IST1 and CHMP1B to LDs via its MIT domain to facilitate LD-to-peroxisome FA trafficking, possibly through IST1 and CHMP1B modifying LD membrane morphology. Furthermore, M1 Spastin, IST1 and CHMP1B are all required to relieve LDs of lipid peroxidation. M1 Spastins dual roles in tethering LDs to peroxisomes and in recruiting ESCRT-components to LD-peroxisome contact sites for FA trafficking may help explain the pathogenesis of diseases associated with defective FA metabolism in LDs and peroxisomes.

cell biology↗

bioRxiv2018

Neuron-astrocyte metabolic coupling during neuronal stimulation protects against fatty acid toxicity

GRAPHICAL ABSTACT\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=165 SRC=\"FIGDIR/small/465237_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (57K):\norg.highwire.dtl.DTLVardef@1d6cbf4org.highwire.dtl.DTLVardef@e83c9corg.highwire.dtl.DTLVardef@e35b92org.highwire.dtl.DTLVardef@910303_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIHyperactive neurons generate and release excess peroxidated fatty acids (FAs)\nC_LIO_LIAstrocytes endocytose toxic FAs as lipoprotein particles, delivering them to lipid droplets\nC_LIO_LILipid droplets trigger upregulation of genes involved in metabolism and detoxification\nC_LIO_LIAstrocytes detoxify and consume FAs by mitochondrial oxidation in response to neural activity\nC_LI\n\nSUMMARYMetabolic coordination between neurons and astrocytes is critical for the health of the brain. However, neuron-astrocyte coupling of lipid metabolism, particularly in response to neural activity, remains largely uncharacterized. Here, we demonstrate that toxic, peroxidated fatty acids (FAs) produced in hyperactive neurons are transferred to astrocytic lipid droplets by lipoprotein particles. Astrocytes consume the FAs stored in lipid droplets via mitochondrial {beta}-oxidation in response to neuronal activity and turn on a detoxification gene expression program. Together, our findings reveal that FA metabolism between neurons and astrocytes is coupled in an activity-dependent manner to protect neurons from FA toxicity. This coordinated mechanism for metabolizing FAs could underlie both homeostasis and a variety of disease states of the brain.

neuroscience↗