Recycling endosomes associate with Golgi stacks in sea urchin embryos

ABSTRACT

The trans-Golgi network (TGN) and recycling endosome (RE) have been recognized as sorting centers, the former for newly synthesized and the latter for endocytosed proteins. However, recent findings have revealed that TGN also receives endocytosed materials and RE accepts newly synthesized proteins destined to the plasma membrane. Recently, we reported that in both Drosophila and microtubule-disrupted HeLa cells, REs are associated with the trans-side of Golgi stacks. REs are highly dynamic: their separation from and association with Golgi stacks are often observed. Importantly, a newly synthesized cargo, glycosylphosphatidylinositol-anchored-GFP was found to be concentrated in Golgi-associated REs (GA-REs), while another cargo VSVG-GFP was excluded from GA-REs before post-Golgi trafficking to the plasma membrane. This suggested that the sorting of cargos takes place at the interface of Golgi stacks and GA-REs. In this study, we demonstrated that REs could associate with Golgi stacks in sea urchin embryos, further indicating that the association of REs with Golgi stacks is a well-conserved phenomenon in the animal kingdom.

KEYWORDS:

• Recycling endosome
• trans-Golgi network
• sea urchin
• Golgi stack
• embryo
• mRNA injection

Acknowledgments

We thank Dr. Masato Kiyomoto (Tateyama Marine Laboratory, Marine and Coastal Research Center, Ochanomizu University) for supplying live sea urchins to conduct the experiments. This work was supported by the Precursory Research for Embryonic Science and Technology under grant no. 25-J-J4215]; Japan Society for the Promotion of Science to A. S. under grant no. 15K07050; Sumitomo Foundation for Basic Science Research Projects, Astellas Foundation for Research on Metabolic Disorders, and Female Researcher Joint Research Grant from Hiroshima University to A.S. and T.S. under grant no. 19K06566. We would like to thank Editage (www.editage.com) for providing assistance in English language editing.

Disclosure statement

All authors have read and approved this work and they report no conflict of interest.

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science, KAKENHI [19K06566]; Japan Society for the Promotion of Science, KAKENHI [15K07050]; the Precursory Research for Embryonic Science and Technology [25-J-J4215].