EFA6A, an Exchange Factor for Arf6, Regulates NGF‐Dependent TrkA Recycling From Early Endosomes and Neurite Outgrowth in PC12 Cells

• Published in: Traffic (Copenhagen, Denmark) Denmark), 2024-05, Vol.25 (5), p.e12936-n/a
• Main Authors: Fukaya, Masahiro, Ibuchi, Kanta, Sugawara, Takeyuki, Itakura, Makoto, Ito, Akiko, Shiroshima, Tomoko, Hara, Yoshinobu, Okamoto, Hirotsugu, Luton, Frédéric, Sakagami, Hiroyuki
• Format: Article
• Language: English
• Subjects: Actin; ADP-Ribosylation Factor 6; ADP-Ribosylation Factors - genetics; ADP-Ribosylation Factors - metabolism; Animals; Arf6; Axonogenesis; Cell differentiation; Cell surface; Cell survival; Cytoskeleton; Dorsal root ganglia; DRG; EFA6A; endosomal trafficking; Endosomes; Endosomes - metabolism; Extracellular signal-regulated kinase; Ganglia, Spinal - metabolism; Guanine nucleotide exchange factor; Guanine Nucleotide Exchange Factors - genetics; Guanine Nucleotide Exchange Factors - metabolism; Mice; Mice, Knockout; Nerve growth factor; Nerve Growth Factor - metabolism; neurite outgrowth; Neuronal Outgrowth; Neurons; PC12; PC12 Cells; Pheochromocytoma cells; Phosphorylation; Protein Transport; Protein turnover; Rats; Receptor, trkA - metabolism; recycling; Ribosylation; TrkA; TrkA protein; TrkA receptors
• ISSN: 1398-9219; 1600-0854; 1600-0854
• DOI: 10.1111/tra.12936

ABSTRACT Endosomal trafficking of TrkA is a critical process for nerve growth factor (NGF)‐dependent neuronal cell survival and differentiation. The small GTPase ADP‐ribosylation factor 6 (Arf6) is implicated in NGF‐dependent processes in PC12 cells through endosomal trafficking and actin cytoskeleton reorganization. However, the regulatory mechanism for Arf6 in NGF signaling is largely unknown. In this study, we demonstrated that EFA6A, an Arf6‐specific guanine nucleotide exchange factor, was abundantly expressed in PC12 cells and that knockdown of EFA6A significantly inhibited NGF‐dependent Arf6 activation, TrkA recycling from early endosomes to the cell surface, prolonged ERK1/2 phosphorylation, and neurite outgrowth. We also demonstrated that EFA6A forms a protein complex with TrkA through its N‐terminal region, thereby enhancing its catalytic activity for Arf6. Similarly, we demonstrated that EFA6A forms a protein complex with TrkA in cultured dorsal root ganglion (DRG) neurons. Furthermore, cultured DRG neurons from EFA6A knockout mice exhibited disturbed NGF‐dependent TrkA trafficking compared with wild‐type neurons. These findings provide the first evidence for EFA6A as a key regulator of NGF‐dependent TrkA trafficking and signaling. We revealed that EFA6A regulates recycling of internalized TrkA to the cell surface and sustained ERK1/2 activation upon NGF stimulation in PC12 cells, and that EFA6A interacts with TrkA, thereby facilitating the activation of Arf6. Furthermore, we showed that EFA6A forms a protein complex with TrkA in DRG neurons and that NGF‐dependent TrkA trafficking is disturbed in EFA6A‐KO DRG neurons. The present study provides the first evidence for EFA6A as a critical regulator of NGF‐dependent TrkA trafficking.