DDHD1, but Not DDHD2, Suppresses Neurite Outgrowth in SH-SY5Y and PC12 Cells by Regulating Protein Transport From Recycling Endosomes

Yuki Maemoto; Tomohiro Maruyama; Kazuaki Nemoto; Takashi Baba; Manae Motohashi; Akihiro Ito; Mitsuo Tagaya; Katsuko Tani

doi:10.3389/fcell.2020.00670

DDHD1, but Not DDHD2, Suppresses Neurite Outgrowth in SH-SY5Y and PC12 Cells by Regulating Protein Transport From Recycling Endosomes

Front Cell Dev Biol. 2020 Jul 23:8:670. doi: 10.3389/fcell.2020.00670. eCollection 2020.

Authors

Yuki Maemoto¹, Tomohiro Maruyama¹, Kazuaki Nemoto¹, Takashi Baba^{1

2}, Manae Motohashi¹, Akihiro Ito¹, Mitsuo Tagaya¹, Katsuko Tani¹

Affiliations

¹ School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan.
² Department of Biological Informatics and Experimental Therapeutics, Graduate School of Medicine and Faculty of Medicine, Akita University, Akita, Japan.

Abstract

DDHD1 and DDHD2 are both intracellular phospholipases A₁ and hydrolyze phosphatidic acid in vitro. Given that phosphatidic acid participates in neurite outgrowth, we examined whether DDHD1 and DDHD2 regulate neurite outgrowth. Depletion of DDHD1 from SH-SY5Y and PC12 cells caused elongation of neurites, whereas DDHD2 depletion prevented neurite elongation. Rescue experiments demonstrated that the enzymatic activity of DDHD1 is necessary for the prevention of neurite elongation. Depletion of DDHD1 caused enlargement of early endosomes and stimulated tubulation of recycling endosomes positive for phosphatidic acid-binding proteins syndapin2 and MICAL-L1. Knockout of DDHD1 enhanced transferrin recycling from recycling endosomes to the cell surface. Our results suggest that DDHD1 negatively controls the formation of a local phosphatidic acid-rich domain in recycling endosomes that serves as a membrane source for neurite outgrowth.

Keywords: endosome; neurite; phosphatidic acid; phospholipase; recycling.