title: Early eukaryotic origins for cilia-associated bioactive peptide-amidating activity.
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.
authors.affiliation: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3401, USA.
authors.forename: Dhivya
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA.
authors.forename: Crysten E
authors.initials: CE
authors.lastname: Blaby-Haas
authors.affiliation: 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.
authors.forename: Sabeeha S
authors.initials: SS
authors.lastname: Merchant
authors.affiliation: Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Mains
authors.affiliation: Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3401, USA eipper@uchc.edu sking@uchc.edu.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: King
authors.affiliation: 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 eipper@uchc.edu sking@uchc.edu.
authors.forename: Betty A
authors.initials: BA
authors.lastname: Eipper
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000201:enzymology* / Q000648:ultrastructure; D002923:Cilia / Q000201:enzymology*; D019143:Evolution, Molecular; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D019884:Nitrogenous Group Transferases / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021381:Protein Transport
chemical_list: D010940:Plant Proteins; D019884:Nitrogenous Group Transferases
keywords: Amidation; Axoneme; Chlamydomonas; Cuproenzyme; Monooxygenase; Neuropeptide