Article: Scientists discover that cells contain mitochondria specialized to build fats

[Indigophoton]

The discovery of a subset of mitochondria that have a different type of function.

Mitochondria, known to most people as the "powerhouses of the cell," have been recognized for decades as the cellular organelle where sugars and fats are oxidized to generate energy. Now, new research by UCLA scientists has found that not all mitochondria fit this definition. Within each cell a group of specialized mitochondria can be found attached to fat droplets. Rather than burn fat to create energy, these specialized mitochondria are responsible for providing the energy to build and store fat molecules.

"This is really a whole new view of mitochondria and what they can do," said lead author Dr. Orian Shirihai, a professor of medicine in endocrinology and pharmacology at the David Geffen School of Medicine at UCLA. The finding, published in Cell Metabolism, may one day lead to new treatments for obesity, fatty liver and other metabolic diseases, he added.

The finding also calls into question traditional techniques used to study mitochondria. To isolate mitochondria for research, scientists generally use protocols that separate the organelles from other components of cells—including fats, which are discarded. Now, it turns out, those trashed fats likely included a subset of previously unexplored mitochondria.
"We've been systematically throwing away all these lipid-associated mitochondria in all this research that's been done on mitochondria in the past," Shirihai said.

https://phys.org/news/2018-04-scientists-cells-mitochondria-specialized-fats.amp

The full paper is here,

Highlights

• •Peridroplet mitochondria (PDM) have enhanced bioenergetic capacity
• •Peridroplet mitochondria have low fatty acid oxidation capacity
• •PDM support lipid droplet expansion by providing ATP for triacylglyceride synthesis
• •Distinct fusion-fission dynamics separate PDM from cytoplasmic mitochondria

Summary

Mitochondria associate with lipid droplets (LDs) in fat-oxidizing tissues, but the functional role of these peridroplet mitochondria (PDM) is unknown. Microscopic observation of interscapular brown adipose tissue reveals that PDM have unique protein composition and cristae structure and remain adherent to the LD in the tissue homogenate. We developed an approach to isolate PDM based on their adherence to LDs. Comparison of purified PDM to cytoplasmic mitochondria reveals that (1) PDM have increased pyruvate oxidation, electron transport, and ATP synthesis capacities; (2) PDM have reduced β-oxidation capacity and depart from LDs upon activation of brown adipose tissue thermogenesis and β-oxidation; (3) PDM support LD expansion as Perilipin5-induced recruitment of mitochondria to LDs increases ATP synthase-dependent triacylglyceride synthesis; and (4) PDM maintain a distinct protein composition due to uniquely low fusion-fission dynamics. We conclude that PDM represent a segregated mitochondrial population with unique structure and function that supports triacylglyceride synthesis.

 

[Wonko]

So, given the worldwide obesity "epidemic" shouldn't someone be looking for a way of telling them to slow down, take it easy, have a beer etc.

Probably not the reason for the thread but hey, it's a thought.

 

[Indigophoton]

@Wonko you've invented CBT for fat-building mitos...

 

[Snow Leopard]

I've had a hypothesis around dysfunction of lipid metabolism for a while now, but dismissed it given certain mito evidence... Now having another think.