1
|
Durand L, Duval S, Evagelidis A, Guillemot J, Dianati V, Sikorska E, Schu P, Day R, Seidah NG. The motif E XE XXXL in the cytosolic tail of the secretory human proprotein convertase PC7 regulates its trafficking and cleavage activity. J Biol Chem 2020; 295:2068-2083. [PMID: 31915245 DOI: 10.1074/jbc.ra119.011775] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/17/2019] [Indexed: 02/05/2023] Open
Abstract
Many secretory proteins are activated by cleavage at specific sites. The proprotein convertases (PCs) form a family of nine secretory subtilisin-like serine proteases, seven of which cleave at specific basic residues within the trans-Golgi network, granules, or at the cell surface/endosomes. The seventh member, PC7, is a type-I transmembrane (TM) protein with a 97-residue-long cytosolic tail (CT). PC7 sheds human transferrin receptor 1 (hTfR1) into soluble shTfR1 in endosomes. To better understand the physiological roles of PC7, here we focused on the relationship between the CT-regulated trafficking of PC7 and its ability to shed hTfR1. Deletion of the TMCT resulted in soluble PC7 and loss of its hTfR1 shedding activity. Extensive CT deletions and mutagenesis analyses helped us zoom in on three residues in the CT, namely Glu-719, Glu-721, and Leu-725, that are part of a novel motif, EXEXXXL725, critical for PC7 activity on hTfR1. NMR studies of two 14-mer peptides mimicking this region of the CT and its Ala variants revealed that the three exposed residues are on the same side of the molecule. This led to the identification of adaptor protein 2 (AP-2) as a protein that recognizes the EXEXXXL725 motif, thus representing a potentially new regulator of PC7 trafficking and cleavage activity. Immunocytochemistry of the subcellular localization of PC7 and its Ala variants of Leu-725 and Glu-719 and Glu-721 revealed that Leu-725 enhances PC7 localization to early endosomes and that, together with Glu-719 and Glu-721, it increases the endosomal activity of PC7 on hTfR1.
Collapse
Affiliation(s)
- Loreleï Durand
- Laboratory of Biochemical Neuroendocrinology, Clinical Research of Montreal, affiliated with Université de Montréal, Montreal, Quebec H2W 1R7, Canada
| | - Stéphanie Duval
- Laboratory of Biochemical Neuroendocrinology, Clinical Research of Montreal, affiliated with Université de Montréal, Montreal, Quebec H2W 1R7, Canada
| | - Alexandra Evagelidis
- Laboratory of Biochemical Neuroendocrinology, Clinical Research of Montreal, affiliated with Université de Montréal, Montreal, Quebec H2W 1R7, Canada
| | - Johann Guillemot
- CIRI, Centre International de Recherche en Infectiologie, Team Pathogenesis of Legionella, INSERM U1111, Université Claude Bernard Lyon 1, CNRS UMR5308, École Normale Supérieure de Lyon, Université Lyon, Villeurbanne, 69100 France
| | - Vahid Dianati
- Institut de Pharmacologie de Sherbrooke, Department of Surgery/Urology Division, and Faculté de Médecine et des Sciences de la Santé, Sherbrooke, Quebec J 1H 5N4, Canada
| | - Emilia Sikorska
- Faculty of Chemistry, University of Gdańsk, Gdańsk, 80-233 Poland
| | - Peter Schu
- Department of Cellular Biochemistry, University Medical Center, Göttingen, Humboldtallee 23, 37073 Goettingen, Germany
| | - Robert Day
- Institut de Pharmacologie de Sherbrooke, Department of Surgery/Urology Division, and Faculté de Médecine et des Sciences de la Santé, Sherbrooke, Quebec J 1H 5N4, Canada
| | - Nabil G Seidah
- Laboratory of Biochemical Neuroendocrinology, Clinical Research of Montreal, affiliated with Université de Montréal, Montreal, Quebec H2W 1R7, Canada.
| |
Collapse
|