title: Regulation of N-Formyl Peptide Receptor Signaling and Trafficking by Arrestin-Src Kinase Interaction.
abstract: Arrestins were originally described as proteins recruited to ligand-activated, phosphorylated G protein-coupled receptors (GPCRs) to attenuate G protein-mediated signaling. It was later revealed that arrestins also mediate GPCR internalization and recruit a number of signaling proteins including, but not limited to, Src family kinases, ERK1/2, and JNK3. GPCR-arrestin binding and trafficking control the spatial and temporal activity of these multi-protein complexes. In previous reports, we concluded that N-formyl peptide receptor (FPR)-mediated apoptosis, which occurs upon receptor stimulation in the absence of arrestins, is associated with FPR accumulation in perinuclear recycling endosomes. Under these conditions, inhibition of Src kinase and ERK1/2 prevented FPR-mediated apoptosis. To better understand the role of Src kinase in this process, in the current study we employed a previously described arrestin-2 (arr2) mutant deficient in Src kinase binding (arr2-P91G/P121E). Unlike wild type arrestin, arr2-P91G/P121E did not inhibit FPR-mediated apoptosis, suggesting that Src binding to arrestin-2 prevents apoptotic signaling. However, in cells expressing this mutant, FPR-mediated apoptosis was still blocked by inhibition of Src kinase activity, suggesting that activation of Src independent of arrestin-2 binding is involved in FPR-mediated apoptosis. Finally, while Src kinase inhibition prevented FPR-mediated-apoptosis in the presence of arr2-P91G/P121E, it did not prevent FPR-arr2-P91G/P121E accumulation in the perinuclear recycling endosome. On the contrary, inhibition of Src kinase activity mediated the accumulation of activated FPR-wild type arrestin-2 in recycling endosomes without initiating FPR-mediated apoptosis. Based on these observations, we conclude that Src kinase has two independent roles following FPR activation that regulate both FPR-arrestin-2 signaling and trafficking.
authors.affiliation: Department of Internal Medicine and UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, United States of America.
authors.forename: Brant M
authors.initials: BM
authors.lastname: Wagener
authors.affiliation: Department of Internal Medicine and UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, United States of America.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Marjon
authors.affiliation: Department of Internal Medicine and UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, United States of America.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Prossnitz
mesh_terms: D000818:Animals; D017209:Apoptosis; D019390:Arrestins / Q000502:physiology*; D002465:Cell Movement; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation; D011485:Protein Binding; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D044042:Receptors, Formyl Peptide / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D019390:Arrestins; D012333:RNA, Messenger; D044042:Receptors, Formyl Peptide; D019061:src-Family Kinases