Journal News

MCP: Worms, too, slow down
in old age

John Arnst
September 01, 2017

In efforts to stave off death, unicellular and multicellular organisms constantly are recycling proteins, breaking down those that are damaged to provide building blocks for fresh copies that can carry out cellular functions. The process is an uphill battle with an inevitable end: The recycling and refreshing slow down, causing cellular damage to continue accruing until the organism dies and ultimately is broken into biochemical materials for other life. This progression, known as senescence, occurs in nearly every organism on Earth and has been studied extensively in the model organism Caenorhabditis elegans.

MCP-worms,-too,-slow-down-in-old-age-load.jpg

The roundworms’ decrease in protein turnover doesn’t occur evenly, however. Researchers at Ghent University in Belgium recently determined that two families of proteins involved in intracellular movement and reproduction are especially hard-hit in the worms.

“It’s not a uniform slowdown of the whole set of proteins,” said Ineke Dhondt, a postdoctoral researcher in the university’s Laboratory for Aging Physiology and Molecular Evolution. Dhondt and colleagues at the Pacific Northwestern National Laboratory in Washington recently described their findings in the journalMolecular & Cellular Proteomics. Previous papers in the field had determined that protein turnover in C. elegans decreases with age but hadn’t examined how significantly the effects varied between different families of proteins. “There are proteins that keep or retain their turnover,” Dhondt said. “That might be quite a different insight from other studies that only focus on the bulk protein turnover.”

C. elegans are widely used to study aging due to their short lifespan and well-characterized genomes. To examine which proteins were being turned over, the researchers fed subpopulations of the worms alternating samples of the bacteria Escherichia coli grown with either heavy or light nitrogen isotopes, characterizing the worms’ protein production with mass spectrometry before and after each meal over several days. The difference in isotope weights causes a slight weight difference in proteins that are subsequently synthesized, which can yield information about changes in protein production when compared with the previous spectrometer readings.

Dhondt and her colleagues found that the worms were decreasing their turnover of proteins in the tubulin and vitellogenin families, which are involved in cytoskeletal movement and production of eggs, respectively. They also found that ribosomal proteins, which are responsible for protein synthesis and all generally have a similar half-life, ended up varying widely in their turnover rates.

“We saw that these protein-turnover values really fan out over time,” Dhondt said. “That was an indication that this group might be important to dysregulation of the protein synthesis phenomenon, and that actually can be a key component to underlie aging.”

They also found that proteins responsible for protein degradation, such as the ubiquitin system, tended to continue their turnover throughout aging. “It’s like (the worms) want to keep up their function, so by refreshing these proteins, they want to make sure that these proteins keep functioning,” Dhondt said. “But in the end they’re fighting a battle that they can’t win, because the whole proteome will ultimately collapse.”

Dhondt and colleagues plan to continue studying aging in roundworms, with a new focus on the quality of health the worms exhibit into old age. “An important parameter for us is to look at the ability of the worms to move,” she said. “We are checking not only if the worms are living longer from a certain treatment but whether they are also exhibiting better health.”

John Arnst

John Arnst was a science writer for ASBMB Today.

Join the ASBMB Today mailing list

Sign up to get updates on articles, interviews and events.

Latest in Science

Science highlights or most popular articles

Brain Injury Awareness Month 2021
Health Observance

Brain Injury Awareness Month 2021

March 01, 2021

In the U.S., about 2.8 million people sustain a traumatic brain injury annually. Learn about recent research on TBI-related dementia, dysfunctional mitochondria and other work powering the march toward better therapies.

The evolution of proteins from mysteries to medicines
Essay

The evolution of proteins from mysteries to medicines

February 27, 2021

An essay in observance of National Protein Day.

'Every experiment and every breakthrough matters'
Health Observance

'Every experiment and every breakthrough matters'

February 26, 2021

An interview with NYMC dean Marina K. Holz, who studies a rare disease that affects women of childbearing age.

Progeria: From the unknown to the first FDA-approved treatment
Health Observance

Progeria: From the unknown to the first FDA-approved treatment

February 25, 2021

Hutchinson–Gilford progeria syndrome is a rare, fatal genetic disease that causes premature aging.

Raising awareness and funding for Pompe disease
Health Observance

Raising awareness and funding for Pompe disease

February 25, 2021

Father-turned-advocate has founded multiple organizations to support families and search for better therapies for people with rare lysosomal storage disorder.

A novel approach to septic shock leads to a prospective new therapy
Journal News

A novel approach to septic shock leads to a prospective new therapy

February 23, 2021

A French research team finds new evidence supporting endotoxin removal for treating life-threatening inflammation.