Functional identification of three receptor activator of NF-kappa B cytoplasmic motifs mediating osteoclast differentiation and function.
Receptor activator of NF-kappa B ligand (RANKL) and its receptor activator of NF-kappa B (RANK) play pivotal roles in osteoclast differentiation and function. However, the structural determinants of the RANK that mediate osteoclast formation and function have not been definitively identified. To address this issue, we developed a chimeric receptor approach that permits a structure/function study of the RANK cytoplasmic domain in osteoclasts. Using this approach, we examined the role of six RANK putative tumor necrosis factor receptor-associated factor-binding motifs (PTM) (PTM1, ILLMT-REE(286-293); PTM2, PSQPS(349-353); PTM3, PFQEP(369-373); PTM4, VYVSQTSQE(537-545); PTM5, PVQEET(559-564); and PTM6, PVQEQG(604-609)) in osteoclast formation and function. Our data revealed that the RANK cytoplasmic domain possesses three functional motifs (PFQEP(369-373), PVQEET(559-564), and PVQEQG(604-609)) capable of mediating osteoclast formation and function. Moreover, we demonstrated that these motifs play distinct roles in activating intracellular signaling. PFQEP(369-373) initiates NF-kappa B, c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38 signaling pathways and PVQEET(559-564) activates NF-kappa B and p38 pathways in osteoclasts, whereas PVQEQG(604-609) is only capable of activating NF-kappa B pathway. Significantly, the revelation of these functional RANK cytoplasmic motifs has not only laid a foundation for further delineating RANK signaling pathways in osteoclasts, but, more importantly, these RANK motifs themselves represent potential therapeutic targets for bone disorders such as osteoporosis.
Liu
Wei
W
Department of Pathology, University of Alabama at Birmingham, Alabama 35294, USA.
Xu
Duorong
D
Yang
Hongmei
H
Xu
Hui
H
Shi
Zhenqi
Z
Cao
Xuemei
X
Takeshita
Sunao
S
Liu
Jianzhong
J
Teale
Michael
M
Feng
Xu
X
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D002454:Cell Differentiation; D003593:Cytoplasm / Q000737:chemistry*; D005434:Flow Cytometry; D015870:Gene Expression; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000502:physiology; D010010:Osteoclasts / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018124:Receptors, Tumor Necrosis Factor / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D047888:Receptors, Tumor Necrosis Factor, Type I; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D053319:Tumor Necrosis Factor Decoy Receptors; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D010446:Peptide Fragments; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D011993:Recombinant Fusion Proteins; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D053319:Tumor Necrosis Factor Decoy Receptors; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha; C069521:recombinant human tumor necrosis factor-binding protein-1; D016173:Macrophage Colony-Stimulating Factor