title: Mesencephalic astrocyte-derived neurotrophic factor (MANF) secretion and cell surface binding are modulated by KDEL receptors.
abstract: Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER) stress-responsive protein with neuroprotective effects in animal models of neurodegeneration, but the underlying mechanism is not understood. We constructed a set of lentiviral vectors that contain or lack the highly conserved final four amino acids of MANF ("RTDL"), which resemble the canonical ER retention signal ("KDEL"), to study MANF regulation in neuroblastoma cells and rat primary cortical neurons. The RTDL sequence was required for both ER retention and secretory response to ER stress. Overexpression of KDEL receptor paralogs (KDELRs) differentially reduced MANF secretion but had no effect on MANF lacking RTDL. MANF binding to the plasma membrane also required the RTDL sequence and was inhibited with a peptide known to interact with KDELRs, suggesting MANF binds KDELRs at the surface. We detected surface localization of FLAG-tagged KDELRs, with levels increasing following ER stress. Our study provides new insight into the regulation of MANF trafficking and has implications for other secreted proteins containing a KDEL-like retention signal.
authors.affiliation: Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland 21224, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Henderson
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Richie
authors.forename: Mikko
authors.initials: M
authors.lastname: Airavaara
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Brandon K
authors.initials: BK
authors.lastname: Harvey
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress; D006801:Humans; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D021382:Protein Sorting Signals / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D051381:Rats; D018000:Receptors, Peptide / Q000235:genetics / Q000378:metabolism*
chemical_list: C064459:KDEL receptor; C099695:MANF protein, human; C546826:MANF protein, rat; D009414:Nerve Growth Factors; D021382:Protein Sorting Signals; D018000:Receptors, Peptide