1
|
Merkler DJ, Hawley AJ, Eipper BA, Mains RE. Peptidylglycine α-amidating monooxygenase as a therapeutic target or biomarker for human diseases. Br J Pharmacol 2022; 179:3306-3324. [PMID: 35124797 PMCID: PMC9177522 DOI: 10.1111/bph.15815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/20/2024] Open
Abstract
Peptides play a key role in controlling many physiological and neurobiological pathways. Many bioactive peptides require a C-terminal α-amide for full activity. The bifunctional enzyme catalysing α-amidation, peptidylglycine α-amidating monooxygenase (PAM), is the sole enzyme responsible for amidated peptide biosynthesis, from Chlamydomonas reinhardtii to Homo sapiens. Many neuronal and endocrine functions are dependent upon amidated peptides; additional amidated peptides are growth promoters in tumours. The amidation reaction occurs in two steps, glycine α-hydroxylation followed by dealkylation to generate the α-amide product. Currently, most potentially useful inhibitors target the first reaction, which is rate-limiting. PAM is a membrane-bound enzyme that visits the cell surface during peptide secretion. PAM is then used again in the biosynthetic pathway, meaning that cell-impermeable inhibitors or inactivators could have therapeutic value for the treatment of cancer or psychiatric abnormalities. To date, inhibitor design has not fully exploited the structures and mechanistic details of PAM.
Collapse
Affiliation(s)
- David J Merkler
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Aidan J Hawley
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Betty A Eipper
- Department of Molecular Biology & Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
| |
Collapse
|
2
|
Novel insights into peptide amidation and amidating activity in the human circulation. Sci Rep 2021; 11:15791. [PMID: 34349173 PMCID: PMC8338962 DOI: 10.1038/s41598-021-95305-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/23/2021] [Indexed: 02/07/2023] Open
Abstract
C-terminal α-amidation is the final and essential step in the biosynthesis of several peptide hormones. Peptidylglycine α-amidating monooxygenase (PAM) is the only known enzyme to catalyse this reaction. PAM amidating activity (AMA) is known to be present in human circulation, but its physiological role and significance as a clinical biomarker remains unclear. We developed a PAM-specific amidation assay that utilizes the naturally occurring substrate Adrenomedullin-Gly (ADM-Gly, 1-53). Using our amidation assay we quantified serum amidating activities in a large population-based cohort of more than 4900 individuals. A correlation of serum amidating activity with several clinical parameters including high blood pressure was observed. Increasing PAM-AMA was an independent predictor of hard outcomes related to hemodynamic stress such as cardiovascular mortality, atrial fibrillation and heart failure during long-term follow-up (8.8 ± 2.5 years). Moreover, results from an animal study in rats utilizing recombinant human PAM provide novel insights into the physiological role of circulating PAM and show its potential significance in circulating peptide amidation.
Collapse
|
3
|
Bäck N, Mains RE, Eipper BA. PAM: diverse roles in neuroendocrine cells, cardiomyocytes, and green algae. FEBS J 2021; 289:4470-4496. [PMID: 34089560 DOI: 10.1111/febs.16049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/28/2021] [Accepted: 06/02/2021] [Indexed: 12/13/2022]
Abstract
Our understanding of the ways in which peptides are used for communication in the nervous and endocrine systems began with the identification of oxytocin, vasopressin, and insulin, each of which is stored in electron-dense granules, ready for release in response to an appropriate stimulus. For each of these peptides, entry of its newly synthesized precursor into the ER lumen is followed by transport through the secretory pathway, exposing the precursor to a sequence of environments and enzymes that produce the bioactive products stored in mature granules. A final step in the biosynthesis of many peptides is C-terminal amidation by peptidylglycine α-amidating monooxygenase (PAM), an ascorbate- and copper-dependent membrane enzyme that enters secretory granules along with its soluble substrates. Biochemical and cell biological studies elucidated the highly conserved mechanism for amidated peptide production and raised many questions about PAM trafficking and the effects of PAM on cytoskeletal organization and gene expression. Phylogenetic studies and the discovery of active PAM in the ciliary membranes of Chlamydomonas reinhardtii, a green alga lacking secretory granules, suggested that a PAM-like enzyme was present in the last eukaryotic common ancestor. While the catalytic features of human and C. reinhardtii PAM are strikingly similar, the trafficking of PAM in C. reinhardtii and neuroendocrine cells and secretion of its amidated products differ. A comparison of PAM function in neuroendocrine cells, atrial myocytes, and C. reinhardtii reveals multiple ways in which altered trafficking allows PAM to accomplish different tasks in different species and cell types.
Collapse
Affiliation(s)
- Nils Bäck
- Department of Anatomy, University of Helsinki, Finland
| | - Richard E Mains
- Department of Neuroscience, UConn Health, Farmington, CT, USA
| | - Betty A Eipper
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| |
Collapse
|
4
|
Güner G, Lichtenthaler SF. The substrate repertoire of γ-secretase/presenilin. Semin Cell Dev Biol 2020; 105:27-42. [PMID: 32616437 DOI: 10.1016/j.semcdb.2020.05.019] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 12/09/2022]
Abstract
The intramembrane protease γ-secretase is a hetero-tetrameric protein complex with presenilin as the catalytic subunit and cleaves its membrane protein substrates within their single transmembrane domains. γ-Secretase is well known for its role in Notch signalling and in Alzheimer's disease, where it catalyzes the formation of the pathogenic amyloid β (Aβ) peptide. However, in the 21 years since its discovery many more substrates and substrate candidates of γ-secretase were identified. Although the physiological relevance of the cleavage of many substrates remains to be studied in more detail, the substrates demonstrate a broad role for γ-secretase in embryonic development, adult tissue homeostasis, signal transduction and protein degradation. Consequently, chronic γ-secretase inhibition may cause significant side effects due to inhibition of cleavage of multiple substrates. This review provides a list of 149 γ-secretase substrates identified to date and highlights by which expeirmental approach substrate cleavage was validated. Additionally, the review lists the cleavage sites where they are known and discusses the functional implications of γ-secretase cleavage with a focus on substrates identified in the recent past, such as CHL1, TREM2 and TNFR1. A comparative analysis demonstrates that γ-secretase substrates mostly have a long extracellular domain and require ectodomain shedding before γ-secretase cleavage, but that γ-secretase is also able to cleave naturally short substrates, such as the B cell maturation antigen. Taken together, the list of substrates provides a resource that may help in the future development of drugs inhibiting or modulating γ-secretase activity in a substrate-specific manner.
Collapse
Affiliation(s)
- Gökhan Güner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675, Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
| |
Collapse
|
5
|
Lindberg I, Glembotski CC. Physiological signaling in the absence of amidated peptides. Proc Natl Acad Sci U S A 2019; 116:19774-19776. [PMID: 31515450 PMCID: PMC6778239 DOI: 10.1073/pnas.1914001116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201;
| | - Christopher C Glembotski
- San Diego State University Heart Institute, San Diego State University, San Diego, CA 92182
- Department of Biology, San Diego State University, San Diego, CA 92182
| |
Collapse
|
6
|
Kumar D, Mains RE, Eipper BA, King SM. Ciliary and cytoskeletal functions of an ancient monooxygenase essential for bioactive amidated peptide synthesis. Cell Mol Life Sci 2019; 76:2329-2348. [PMID: 30879092 PMCID: PMC6529398 DOI: 10.1007/s00018-019-03065-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/28/2019] [Accepted: 03/07/2019] [Indexed: 02/07/2023]
Abstract
Many secreted peptides used for cell-cell communication require conversion of a C-terminal glycine to an amide for bioactivity. This reaction is catalyzed only by the integral membrane protein peptidylglycine α-amidating monooxygenase (PAM). PAM has been highly conserved and is found throughout the metazoa; PAM-like sequences are also present in choanoflagellates, filastereans, unicellular and colonial chlorophyte green algae, dinoflagellates and haptophytes. Recent studies have revealed that in addition to playing a key role in peptidergic signaling, PAM also regulates ciliogenesis in vertebrates, planaria and chlorophyte algae, and is required for the stability of actin-based microvilli. Here we briefly introduce the basic principles involved in ciliogenesis, the sequential reactions catalyzed by PAM and the trafficking of PAM through the secretory and endocytic pathways. We then discuss the multi-faceted roles this enzyme plays in the formation and maintenance of cytoskeleton-based cellular protrusions and propose models for how PAM protein and amidating activity might contribute to ciliogenesis. Finally, we consider why some ciliated organisms lack PAM, and discuss the potential ramifications of ciliary localized PAM for the endocrine features commonly observed in patients with ciliopathies.
Collapse
Affiliation(s)
- Dhivya Kumar
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, 06030, USA
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, 06030, USA
| | - Betty A Eipper
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, 06030, USA
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, 06030, USA
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, 06030, USA.
| |
Collapse
|
7
|
Kumar D, Mains RE, Eipper BA. 60 YEARS OF POMC: From POMC and α-MSH to PAM, molecular oxygen, copper, and vitamin C. J Mol Endocrinol 2016; 56:T63-76. [PMID: 26667899 PMCID: PMC4899100 DOI: 10.1530/jme-15-0266] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 12/14/2015] [Indexed: 12/19/2022]
Abstract
A critical role for peptide C-terminal amidation was apparent when the first bioactive peptides were identified. The conversion of POMC into adrenocorticotropic hormone and then into α-melanocyte-stimulating hormone, an amidated peptide, provided a model system for identifying the amidating enzyme. Peptidylglycine α-amidating monooxygenase (PAM), the only enzyme that catalyzes this modification, is essential; mice lacking PAM survive only until mid-gestation. Purification and cloning led to the discovery that the amidation of peptidylglycine substrates proceeds in two steps: peptidylglycine α-hydroxylating monooxygenase catalyzes the copper- and ascorbate-dependent α-hydroxylation of the peptidylglycine substrate; peptidyl-α-hydroxyglycine α-amidating lyase cleaves the N-C bond, producing amidated product and glyoxylate. Both enzymes are contained in the luminal domain of PAM, a type 1 integral membrane protein. The structures of both catalytic cores have been determined, revealing how they interact with metals, molecular oxygen, and substrate to catalyze both reactions. Although not essential for activity, the intrinsically disordered cytosolic domain is essential for PAM trafficking. A phylogenetic survey led to the identification of bifunctional membrane PAM in Chlamydomonas, a unicellular eukaryote. Accumulating evidence points to a role for PAM in copper homeostasis and in retrograde signaling from the lumen of the secretory pathway to the nucleus. The discovery of PAM in cilia, cellular antennae that sense and respond to environmental stimuli, suggests that much remains to be learned about this ancient protein.
Collapse
Affiliation(s)
- Dhivya Kumar
- Departments of Molecular Biology and BiophysicsUniversity of Connecticut Health Center, Farmington, Connecticut, USA
| | - Richard E Mains
- Department of NeuroscienceUniversity of Connecticut Health Center, Farmington, Connecticut, USA
| | - Betty A Eipper
- Departments of Molecular Biology and BiophysicsUniversity of Connecticut Health Center, Farmington, Connecticut, USA Department of NeuroscienceUniversity of Connecticut Health Center, Farmington, Connecticut, USA
| |
Collapse
|
8
|
Vishwanatha KS, Bäck N, Lam TT, Mains RE, Eipper BA. O-Glycosylation of a Secretory Granule Membrane Enzyme Is Essential for Its Endocytic Trafficking. J Biol Chem 2016; 291:9835-50. [PMID: 26961877 DOI: 10.1074/jbc.m115.711838] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Indexed: 01/08/2023] Open
Abstract
Peptidylglycine α-amidating monooxygenase (PAM) (EC 1.14.17.3) catalyzes peptide amidation, a crucial post-translational modification, through the sequential actions of its monooxygenase (peptidylglycine α-hydroxylating monooxygenase) and lyase (peptidyl-α-hydroxyglycine α-amidating lyase (PAL)) domains. Alternative splicing generates two different regions that connect the protease-resistant catalytic domains. Inclusion of exon 16 introduces a pair of Lys residues, providing a site for controlled endoproteolytic cleavage of PAM and the separation of soluble peptidylglycine α-hydroxylating monooxygenase from membrane-associated PAL. Exon 16 also includes two O-glycosylation sites. PAM-1 lacking both glycosylation sites (PAM-1/OSX; where OSX is O-glycan-depleted mutant of PAM-1) was stably expressed in AtT-20 corticotrope tumor cells. In PAM-1/OSX, a cleavage site for furin-like convertases was exposed, generating a shorter form of membrane-associated PAL. The endocytic trafficking of PAM-1/OSX differed dramatically from that of PAM-1. A soluble fragment of the cytosolic domain of PAM-1 was produced in the endocytic pathway and entered the nucleus; very little soluble fragment of the cytosolic domain was produced from PAM-1/OSX. Internalized PAM-1/OSX was rapidly degraded; unlike PAM-1, very little internalized PAM-1/OSX was detected in multivesicular bodies. Blue native PAGE analysis identified high molecular weight complexes containing PAM-1; the ability of PAM-1/OSX to form similar complexes was markedly diminished. By promoting the formation of high molecular weight complexes, O-glycans may facilitate the recycling of PAM-1 through the endocytic compartment.
Collapse
Affiliation(s)
| | - Nils Bäck
- the Department of Anatomy, Faculty of Medicine, University of Helsinki, Fin-00014, Helsinki, Finland, and
| | - TuKiet T Lam
- the W. M. Keck Foundation Biotechnology Resource Laboratory, Yale/Keck MS and Proteomics Resource, Yale/NIDA Neuroproteomics Center, Yale University, New Haven, Connecticut 06511
| | | | - Betty A Eipper
- From the Departments of Neuroscience and Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut 06030,
| |
Collapse
|
9
|
Kumar D, Blaby-Haas CE, Merchant SS, Mains RE, King SM, Eipper BA. Early eukaryotic origins for cilia-associated bioactive peptide-amidating activity. J Cell Sci 2016; 129:943-56. [PMID: 26787743 DOI: 10.1242/jcs.177410] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 01/13/2016] [Indexed: 01/15/2023] Open
Abstract
Ciliary axonemes and basal bodies were present in the last eukaryotic common ancestor and play crucial roles in sensing and responding to environmental cues. Peptidergic signaling, generally considered a metazoan innovation, is essential for organismal development and homeostasis. Peptidylglycine α-amidating monooxygenase (PAM) is crucial for the last step of bioactive peptide biosynthesis. However, identification of a complete PAM-like gene in green algal genomes suggests ancient evolutionary roots for bioactive peptide signaling. We demonstrate that the Chlamydomonas reinhardtii PAM gene encodes an active peptide-amidating enzyme (CrPAM) that shares key structural and functional features with the mammalian enzyme, indicating that components of the peptide biosynthetic pathway predate multicellularity. In addition to its secretory pathway localization, CrPAM localizes to cilia and tightly associates with the axonemal superstructure, revealing a new axonemal enzyme activity. This localization pattern is conserved in mammals, with PAM present in both motile and immotile sensory cilia. The conserved ciliary localization of PAM adds to the known signaling capabilities of the eukaryotic cilium and provides a potential mechanistic link between peptidergic signaling and endocrine abnormalities commonly observed in ciliopathies.
Collapse
Affiliation(s)
- Dhivya Kumar
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3401, USA
| | - Crysten E Blaby-Haas
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095-1569, USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3401, USA
| | - Betty A Eipper
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3401, USA Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA
| |
Collapse
|
10
|
Antón Palma B, Leff Gelman P, Medecigo Ríos M, Calva Nieves JC, Acevedo Ortuño R, Matus Ortega ME, Hernández Calderón JA, Hernández Miramontes R, Flores Zamora A, Salazar Juárez A. Generation of a novel monoclonal antibody that recognizes the alpha (α)-amidated isoform of a valine residue. BMC Neurosci 2015; 16:65. [PMID: 26463686 PMCID: PMC4603347 DOI: 10.1186/s12868-015-0206-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 10/01/2015] [Indexed: 11/10/2022] Open
Abstract
Background Alpha (α)-amidation of peptides is a mechanism required for the conversion of prohormones into functional peptide sequences that display biological activities, receptor recognition and signal transduction on target cells. Alpha (α)-amidation occurs in almost all species and amino acids identified in nature. C-terminal valine amide neuropeptides constitute the smallest group of functional peptide compounds identified in neurosecretory structures in vertebrate and invertebrate species. Methods The α-amidated isoform of valine residue (Val-CONH2) was conjugated to KLH-protein carrier and used to immunize mice. Hyperimmune animals displaying high titers of valine amide antisera were used to generate stable hybridoma-secreting mAbs. Three productive hybridoma (P15A4, P17C11, and P18C5) were tested against peptides antigens containing both the C-terminal α-amidated (–CONH2) and free α-carboxylic acid (−COO−) isovariant of the valine residue. Results P18C5 mAb displayed the highest specificity and selectivity against C-terminal valine amidated peptide antigens in different immunoassays. P18C5 mAb-immunoreactivity exhibited a wide distribution along the neuroaxis of the rat brain, particularly in brain areas that did not cross-match with the neuronal distribution of known valine amide neuropeptides (α-MSH, adrenorphin, secretin, UCN1-2). These brain regions varied in the relative amount of putative novel valine amide peptide immunoreactive material (nmol/μg protein) estimated through a fmol-sensitive solid-phase radioimmunoassay (RIA) raised for P18C5 mAb. Conclusions Our results demonstrate the versatility of a single mAb able to differentiate between two structural subdomains of a single amino acid. This mAb offers a wide spectrum of potential applications in research and medicine, whose uses may extend from a biological reagent (used to detect valine amidated peptide substances in fluids and tissues) to a detoxifying reagent (used to neutralize exogenous toxic amide peptide compounds) or as a specific immunoreagent in immunotherapy settings (used to reduce tumor growth and tumorigenesis) among many others.
Collapse
Affiliation(s)
- Benito Antón Palma
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Philippe Leff Gelman
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico. .,Department of Neuroscience, National Institute of Perinatology, Montes Urales # 800, 11000, México D.F., Mexico.
| | - Mayra Medecigo Ríos
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Juan Carlos Calva Nieves
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Rodolfo Acevedo Ortuño
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Maura Epifanía Matus Ortega
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Jorge Alberto Hernández Calderón
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Ricardo Hernández Miramontes
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Anabel Flores Zamora
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| | - Alberto Salazar Juárez
- Molecular Neurobiology and Addictive Neurochemistry Laboratory, National Institute of Psychiatry, Calzada México-Xochimilco #101, 14370, México D.F., Mexico.
| |
Collapse
|
11
|
Bonnemaison ML, Bäck N, Duffy ME, Ralle M, Mains RE, Eipper BA. Adaptor Protein-1 Complex Affects the Endocytic Trafficking and Function of Peptidylglycine α-Amidating Monooxygenase, a Luminal Cuproenzyme. J Biol Chem 2015; 290:21264-79. [PMID: 26170456 DOI: 10.1074/jbc.m115.641027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Indexed: 11/06/2022] Open
Abstract
The adaptor protein-1 complex (AP-1), which transports cargo between the trans-Golgi network and endosomes, plays a role in the trafficking of Atp7a, a copper-transporting P-type ATPase, and peptidylglycine α-amidating monooxygenase (PAM), a copper-dependent membrane enzyme. Lack of any of the four AP-1 subunits impairs function, and patients with MEDNIK syndrome, a rare genetic disorder caused by lack of expression of the σ1A subunit, exhibit clinical and biochemical signs of impaired copper homeostasis. To explore the role of AP-1 in copper homeostasis in neuroendocrine cells, we used corticotrope tumor cells in which AP-1 function was diminished by reducing expression of its μ1A subunit. Copper levels were unchanged when AP-1 function was impaired, but cellular levels of Atp7a declined slightly. The ability of PAM to function was assessed by monitoring 18-kDa fragment-NH2 production from proopiomelanocortin. Reduced AP-1 function made 18-kDa fragment amidation more sensitive to inhibition by bathocuproine disulfonate, a cell-impermeant Cu(I) chelator. The endocytic trafficking of PAM was altered, and PAM-1 accumulated on the cell surface when AP-1 levels were reduced. Reduced AP-1 function increased the Atp7a presence in early/recycling endosomes but did not alter the ability of copper to stimulate its appearance on the plasma membrane. Co-immunoprecipitation of a small fraction of PAM and Atp7a supports the suggestion that copper can be transferred directly from Atp7a to PAM, a process that can occur only when both proteins are present in the same subcellular compartment. Altered luminal cuproenzyme function may contribute to deficits observed when the AP-1 function is compromised.
Collapse
Affiliation(s)
| | - Nils Bäck
- the Department of Anatomy, Faculty of Medicine, University of Helsinki, FIN-00014 Helsinki, Finland, and
| | - Megan E Duffy
- the Department of Molecular and Medical Genetics, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Martina Ralle
- the Department of Molecular and Medical Genetics, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Richard E Mains
- Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Betty A Eipper
- From the Departments of Molecular Biology and Biophysics and Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030,
| |
Collapse
|
12
|
Bonnemaison M, Bäck N, Lin Y, Bonifacino JS, Mains R, Eipper B. AP-1A controls secretory granule biogenesis and trafficking of membrane secretory granule proteins. Traffic 2014; 15:1099-121. [PMID: 25040637 DOI: 10.1111/tra.12194] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 02/06/2023]
Abstract
The adaptor protein 1A complex (AP-1A) transports cargo between the trans-Golgi network (TGN) and endosomes. In professional secretory cells, AP-1A also retrieves material from immature secretory granules (SGs). The role of AP-1A in SG biogenesis was explored using AtT-20 corticotrope tumor cells expressing reduced levels of the AP-1A μ1A subunit. A twofold reduction in μ1A resulted in a decrease in TGN cisternae and immature SGs and the appearance of regulated secretory pathway components in non-condensing SGs. Although basal secretion of endogenous SG proteins was unaffected, secretagogue-stimulated release was halved. The reduced μ1A levels interfered with the normal trafficking of carboxypeptidase D (CPD) and peptidylglycine α-amidating monooxygenase-1 (PAM-1), integral membrane enzymes that enter immature SGs. The non-condensing SGs contained POMC products and PAM-1, but not CPD. Based on metabolic labeling and secretion experiments, the cleavage of newly synthesized PAM-1 into PHM was unaltered, but PHM basal secretion was increased in sh-μ1A PAM-1 cells. Despite lacking a canonical AP-1A binding motif, yeast two-hybrid studies demonstrated an interaction between the PAM-1 cytosolic domain and AP-1A. Coimmunoprecipitation experiments with PAM-1 mutants revealed an influence of the luminal domains of PAM-1 on this interaction. Thus, AP-1A is crucial for normal SG biogenesis, function and composition.
Collapse
Affiliation(s)
- Mathilde Bonnemaison
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, 06030, USA
| | | | | | | | | | | |
Collapse
|
13
|
Vassar R, Kuhn PH, Haass C, Kennedy ME, Rajendran L, Wong PC, Lichtenthaler SF. Function, therapeutic potential and cell biology of BACE proteases: current status and future prospects. J Neurochem 2014; 130:4-28. [PMID: 24646365 PMCID: PMC4086641 DOI: 10.1111/jnc.12715] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 01/18/2023]
Abstract
The β-site APP cleaving enzymes 1 and 2 (BACE1 and BACE2) were initially identified as transmembrane aspartyl proteases cleaving the amyloid precursor protein (APP). BACE1 is a major drug target for Alzheimer's disease because BACE1-mediated cleavage of APP is the first step in the generation of the pathogenic amyloid-β peptides. BACE1, which is highly expressed in the nervous system, is also required for myelination by cleaving neuregulin 1. Several recent proteomic and in vivo studies using BACE1- and BACE2-deficient mice demonstrate a much wider range of physiological substrates and functions for both proteases within and outside of the nervous system. For BACE1 this includes axon guidance, neurogenesis, muscle spindle formation, and neuronal network functions, whereas BACE2 was shown to be involved in pigmentation and pancreatic β-cell function. This review highlights the recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer's disease. The protease BACE1 is a major drug target in Alzheimer disease. Together with its homolog BACE2, both proteases have an increasing number of functions within and outside of the nervous system. This review highlights recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer disease.
Collapse
Affiliation(s)
- Robert Vassar
- Department of Cell and Molecular Biology, Feinberg University School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peer-Hendrik Kuhn
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
- Adolf-Butenandt Institute, Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Matthew E. Kennedy
- Neurosciences, Merck Research Labs, Boston, Massachusetts, USA
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
- Graduate programs of the Zurich Center for Integrative Human Physiology and Zurich Neuroscience Center, University of Zurich, Zurich, Switzerland
| | - Philip C. Wong
- Departments of Pathology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stefan F. Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| |
Collapse
|
14
|
Vishwanatha K, Bäck N, Mains RE, Eipper BA. A histidine-rich linker region in peptidylglycine α-amidating monooxygenase has the properties of a pH sensor. J Biol Chem 2014; 289:12404-20. [PMID: 24627494 DOI: 10.1074/jbc.m113.545947] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Decreasing luminal pH is thought to play a role in the entry of newly synthesized and endocytosed membrane proteins into secretory granules. The two catalytic domains of peptidylglycine α-amidating monooxygenase (PAM), a type I integral membrane protein, catalyze the sequential reactions that convert peptidyl-Gly substrates into amidated products. We explored the hypothesis that a conserved His-rich cluster (His-Gly-His-His) in the linker region connecting its two catalytic domains senses pH and affects PAM trafficking by mutating these His residues to Ala (Ala-Gly-Ala-Ala; H3A). Purified recombinant wild-type and H3A linker peptides were examined using circular dichroism and tryptophan fluorescence; mutation of the His cluster largely eliminated its pH sensitivity. An enzymatically active PAM protein with the same mutations (PAM-1/H3A) was expressed in HEK293 cells and AtT-20 corticotrope tumor cells. Metabolic labeling followed by immunoprecipitation revealed more rapid loss of newly synthesized PAM-1/H3A than PAM-1; although release of newly synthesized monofunctional PHM/H3A was increased, release of soluble bifunctional PAM/H3A, a product of the endocytic pathway, was decreased. Surface biotinylation revealed rapid loss of PAM-1/H3A, with no detectable return of the mutant protein to secretory granules. Consistent with its altered endocytic trafficking, little PAM-1/H3A was subjected to regulated intramembrane proteolysis followed by release of a small nuclear-targeted cytosolic fragment. AtT-20 cells expressing PAM-1/H3A adopted the morphology of wild-type AtT-20 cells; secretory products no longer accumulated in the trans-Golgi network and secretory granule exocytosis was more responsive to secretagogue.
Collapse
|
15
|
Abstract
Peptide hormones with a C-terminal amide regulate numerous physiological processes and are associated with many disease states. Consequently, the key enzymes involved in their production, peptidylglycine α-amidating monooxygenase and carboxypeptidase E, have been studied intensively. This review surveys what is known about the enzymes themselves and their cofactors, as well as their substrates and competitive and mechanism-based inhibitors.
Collapse
|
16
|
Rajagopal C, Mains RE, Eipper BA. Signaling from the secretory granule to the nucleus. Crit Rev Biochem Mol Biol 2012; 47:391-406. [PMID: 22681236 DOI: 10.3109/10409238.2012.694845] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Neurons and endocrine cells use a complex array of signaling molecules to communicate with each other and with various targets. The majority of these signaling molecules are stored in specialized organelles awaiting release on demand: 40-60 nm vesicles carry conventional or small molecule neurotransmitters, and 200-400 nm granules contain bioactive peptides. The supply of small molecule neurotransmitters is tightly regulated by local feedback of synthetic rates and transport processes at sites of release. The larger granules that contain bioactive peptides present the secretory cell with special challenges, as the peptide precursors are inserted into the lumen of the secretory pathway in the cell soma and undergo biosynthetic processing while being transported to distant sites for eventual secretion. One solution to this dilemma in information handling has been to employ proteolytic cleavage of secretory granule membrane proteins to produce cytosolic fragments that can signal to the nucleus, affecting gene expression. The use of regulated intramembrane proteolysis to signal from secretory granules to the nucleus is compared to its much better understood role in relaying information from the endoplasmic reticulum by SREBP and ATF6 and from the plasma membrane by cadherins, Notch and ErbB4.
Collapse
Affiliation(s)
- Chitra Rajagopal
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT, USA
| | | | | |
Collapse
|
17
|
Abstract
The Alzheimer's disease (AD)-associated amyloid-β protein precursor (AβPP) is cleaved by α-, β-, and presenilin (PS)/γ-secretases through sequential regulated proteolysis. These proteolytic events control the generation of the pathogenic amyloid-β (Aβ) peptide, which excessively accumulates in the brains of individuals afflicted by AD. A growing number of additional proteins cleaved by PS/γ-secretase continue to be discovered. Similarly to AβPP, most of these proteins are type-I transmembrane proteins involved in vital signaling functions regulating cell fate, adhesion, migration, neurite outgrowth, or synaptogenesis. All the identified proteins share common structural features, which are typical for their proteolysis. The consequences of the PS/γ-secretase-mediated cleavage on the function of many of these proteins are largely unknown. Here, we review the current literature on the proteolytic processing mediated by the versatile PS/γ-secretase complex. We begin by discussing the steps of AβPP processing and PS/γ-secretase complex composition and localization, which give clues to how and where the processing of other PS/γ-secretase substrates may take place. Then we summarize the typical features of PS/γ-secretase-mediated protein processing. Finally, we recapitulate the current knowledge on the possible physiological function of PS/γ-secretase-mediated cleavage of specific substrate proteins.
Collapse
Affiliation(s)
- Annakaisa Haapasalo
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, Kuopio, Finland.
| | | |
Collapse
|
18
|
Attenborough RMF, Hayward DC, Kitahara MV, Miller DJ, Ball EE. A "neural" enzyme in nonbilaterian animals and algae: preneural origins for peptidylglycine α-amidating monooxygenase. Mol Biol Evol 2012; 29:3095-109. [PMID: 22496439 DOI: 10.1093/molbev/mss114] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Secreted peptides, produced by enzymatic processing of larger precursor molecules, are found throughout the animal kingdom and play important regulatory roles as neurotransmitters and hormones. Many require a carboxy-terminal modification, involving the conversion of a glycine residue into an α-amide, for their biological activity. Two sequential enzymatic activities catalyze this conversion: a monooxygenase (peptidylglycine α-hydroxylating monooxygenase or PHM) and an amidating lyase (peptidyl-α-hydroxyglycine α-amidating lyase or PAL). In vertebrates, these activities reside in a single polypeptide known as peptidylglycine α-amidating monooxygenase (PAM), which has been extensively studied in the context of neuropeptide modification. Bifunctional PAMs have been reported from some invertebrates, but the phylogenetic distribution of PAMs and their evolutionary relationship to PALs and PHMs is unclear. Here, we report sequence and expression data for two PAMs from the coral Acropora millepora (Anthozoa, Cnidaria), as well as providing a comprehensive survey of the available sequence data from other organisms. These analyses indicate that bifunctional PAMs predate the origins of the nervous and endocrine systems, consistent with the idea that within the Metazoa their ancestral function may have been to amidate epitheliopeptides. More surprisingly, the phylogenomic survey also revealed the presence of PAMs in green algae (but not in higher plants or fungi), implying that the bifunctional enzyme either predates the plant/animal divergence and has subsequently been lost in a number of lineages or perhaps that convergent evolution or lateral gene transfer has occurred. This finding is consistent with recent discoveries that other molecules once thought of as "neural" predate nervous systems.
Collapse
Affiliation(s)
- Rosalind M F Attenborough
- Evolution, Ecology and Genetics, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | | | | | | | | |
Collapse
|
19
|
Yin P, Bousquet-Moore D, Annangudi SP, Southey BR, Mains RE, Eipper BA, Sweedler JV. Probing the production of amidated peptides following genetic and dietary copper manipulations. PLoS One 2011; 6:e28679. [PMID: 22194882 PMCID: PMC3241674 DOI: 10.1371/journal.pone.0028679] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/13/2011] [Indexed: 11/23/2022] Open
Abstract
Amidated neuropeptides play essential roles throughout the nervous and endocrine systems. Mice lacking peptidylglycine α-amidating monooxygenase (PAM), the only enzyme capable of producing amidated peptides, are not viable. In the amidation reaction, the reactant (glycine-extended peptide) is converted into a reaction intermediate (hydroxyglycine-extended peptide) by the copper-dependent peptidylglycine-α-hydroxylating monooxygenase (PHM) domain of PAM. The hydroxyglycine-extended peptide is then converted into amidated product by the peptidyl-α-hydroxyglycine α-amidating lyase (PAL) domain of PAM. PHM and PAL are stitched together in vertebrates, but separated in some invertebrates such as Drosophila and Hydra. In addition to its luminal catalytic domains, PAM includes a cytosolic domain that can enter the nucleus following release from the membrane by γ-secretase. In this work, several glycine- and hydroxyglycine-extended peptides as well as amidated peptides were qualitatively and quantitatively assessed from pituitaries of wild-type mice and mice with a single copy of the Pam gene (PAM+/−) via liquid chromatography-mass spectrometry-based methods. We provide the first evidence for the presence of a peptidyl-α-hydroxyglycine in vivo, indicating that the reaction intermediate becomes free and is not handed directly from PHM to PAL in vertebrates. Wild-type mice fed a copper deficient diet and PAM+/− mice exhibit similar behavioral deficits. While glycine-extended reaction intermediates accumulated in the PAM+/− mice and reflected dietary copper availability, amidated products were far more prevalent under the conditions examined, suggesting that the behavioral deficits observed do not simply reflect a lack of amidated peptides.
Collapse
Affiliation(s)
- Ping Yin
- Department of Chemistry, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Danielle Bousquet-Moore
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Suresh P. Annangudi
- Department of Chemistry, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Bruce R. Southey
- Department of Chemistry, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Richard E. Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Betty A. Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- * E-mail: (JVS); (BAE)
| | - Jonathan V. Sweedler
- Department of Chemistry, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail: (JVS); (BAE)
| |
Collapse
|
20
|
Pardossi-Piquard R, Checler F. The physiology of the β-amyloid precursor protein intracellular domain AICD. J Neurochem 2011; 120 Suppl 1:109-124. [PMID: 22122663 DOI: 10.1111/j.1471-4159.2011.07475.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The amyloid-β precursor protein (βAPP) undergoes several cleavages by enzymatic activities called secretases. Numerous studies aimed at studying the biogenesis and catabolic fate of Aβ peptides, the proteinaceous component of the senile plaques that accumulate in Alzheimer's disease-affected brains. Relatively recently, another secretase-mediated β-APP-derived catabolite called APP IntraCellular Domain (AICD) entered the game. Whether AICD corresponded to a biologically inert by-pass product of βAPP processing or whether it could harbor its own function remained questionable. In this study, we review the mechanisms by which AICD is generated and how its production is regulated. Furthermore, we discuss the degradation mechanism underlying its rapid catabolic fate. Finally, we review putative AICD-related functions and more particularly, the numerous studies indicating that AICD could translocate to the nucleus and control at a transcriptional level, the expression of a series of proteins involved in various functions including the control of cell death and Aβ degradation.
Collapse
Affiliation(s)
- Raphaëlle Pardossi-Piquard
- Université de Nice Sophia-Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire UMR6097 CNRS, Equipe labellisée Fondation pour la Recherche Médicale, Sophia-Antipolis, Valbonne, France
| | - Frédéric Checler
- Université de Nice Sophia-Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire UMR6097 CNRS, Equipe labellisée Fondation pour la Recherche Médicale, Sophia-Antipolis, Valbonne, France
| |
Collapse
|
21
|
Cao F, Gamble AB, Kim HK, Onagi H, Gresser MJ, Kerr J, Easton CJ. Potent and selective inhibitors of human peptidylglycine α-amidating monooxygenase. MEDCHEMCOMM 2011. [DOI: 10.1039/c1md00079a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|