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SPL1 Protein Plays a Positive Role in Building Plant Cell Peroxisomes

Plant

The Jianping Hu lab is furthering our knowledge about how the protein, SPL1, helps build peroxisomes in the plant cell. The study is in The Plant Journal.

expand icon Peroxisomes are the plant cell’s food processors. They break down fatty acids (aka, fats) into smaller pieces that end up in energy compounds that power the plants. They also help protect plants from environmental stresses and support the process of photosynthesis.

Scientists are trying to understand how plants build these cellular parts. The knowledge could help us create better plants in the future. It also might benefit the medical field, as humans have peroxisomes and seem to share similar building mechanisms with plants.

The Science

Peroxisomes need two types of proteins to get built:

  1. The builder proteins: called PEX, they come from other parts of the plant cell.
  2. The manager proteins, the focus of the study: they control the import and export of the builders.

Recently, the Hu lab found one protein, SP1, slows the inflow of PEX proteins when there are no ‘building needs.’

Now, they report a new protein, called SPL1, with a different function.

“SPL1 has a more positive role in building the peroxisome. It helps maintain the numbers of some of the builder proteins,” says Jianping Hu, Professor at the MSU-DOE Plant Research Laboratory. “SPL1 does that by restraining the other protein, SP1, that dampens the inflow of the builders.”

In other words, SPL1 is the gas pedal while SP1 puts on the brakes, and plants need both.

“The goal is to maintain the right balance for optimal building activity. That balance ensures plants stay healthy,” Hu says.

“We are also finding that plants use these two proteins to build other plant cell components, in addition to peroxisomes.”

Hu adds that there is evidence that humans, and other species, share similar proteins with plants.

In humans, peroxisomes that go bad can cause severe health problems. Perhaps understanding how they work in plants will lead to new insights in human medicine.

  • Igor Houwat and Jianping Hu via MSU-DOE Plant Research Laboratory News

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