Contrasting Retromer with a Newly Described Retriever in .

The tight regulation of protein composition within the plasma membranes of plant cells is crucial for the proper development of plants and for their ability to respond to a changing environment. Upon being endocytosed, integral membrane proteins can be secreted, sorted into multivesicular bodies/late endosomes, and degraded in the lytic vacuole, or recycled back to the plasma membrane to continue functioning. The evolutionarily conserved retromer complex has attracted the interest of plant cell biologists for over a decade as it has emerged as a key regulator of the trafficking of endocytosed integral plasma membrane proteins.

CCDC22 and CCDC93, two potential retriever-interacting proteins, are required for root and root hair growth in Arabidopsis.

Endomembrane trafficking is essential for plant growth and often depends on a balance between secretory and endocytic pathways. VPS26C is a component of the retriever complex which has been shown to function in the recycling of integral plasma membrane proteins in human cell culture and is part of a core retriever complex in Arabidopsis that is required for root hair growth. In this work, we report a characterization of the Arabidopsis homologues of CCDC22 and CCDC93, two additional proteins required for retriever function in humans.