Proteins that can modify organelles

Just as our body is composed of organs, our cells are composed of organelles of different shapes and functions. Their morphology is essential to their proper functioning and depends on many proteins.

The Cisd family of proteins

A poorly studied family of proteins has attracted the attention of researchers in the laboratory of Prof. Pierre Cosson. Using recombinant antibodies, they have discovered that one member of this family, the Cisd1 protein, plays a role in the structure of mitochondria. Its overexpression causes mitochondria to stick together without fusing as visible in the Figure below.

Intrigued by this first discovery, scientists then studied another member of the family, the Cisd2 protein. In their recent study published in BMC Molecular and Cell Biology, they demonstrate that Cisd2 is located in another organelle, the endoplasmic reticulum, but that it also plays a role in its morphology.

An overexpression of Cisd1 protein modifies the structure of mitochondria : they stick to each other without fusing. Adapted from Figure 4 in Vernay et al. 2017. Copyright 2017 National Academy of Sciences.

What’s next?

These structural discoveries are a first step in the understanding of the role of Cisd proteins. Further functional studies are now needed to define more precisely their roles.

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