Ne mediators in response to chronic Gs activation in OBs were also indentified. All these regulated genes could be used for further functional studies. Biological validation of the role of these mediators may lead to new therapeutic targets for enhancing bone formation in osteoporosis and for reversing bone disease associated with excess Gs signaling.The tension-sensing system that regulates kinetochore-microtubule interactions depends on the Chromosomal Passenger Complex 6, composed of Borealin, Survivin, INCENP, and Aurora B 8. Prior to anaphase, the CPC localizes to inner centromeres, adjacent to sister kinetochores, to monitor inter-kinetochore tension. The prevailing model that explains the role of Aurora B in regulating the SAC posits that under low tension, Aurora B phosphorylates microtubule-binding kinetochore proteins resulting in reduced affinity for microtubules leading to dissociation of kinetochore-microtubule interactions 1014. As chromosomes become bi-oriented and sister kinetochores are under high tension, Aurora B is spatially separated from the kinetochore and can no longer destabilize kinetochoremicrotubule interactions. According to this spatial PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19850363 gradient model, inner centromere localization of the CPC is paramount for error correction 15. In yeast, however, Chebulinic acid chemical information INCENP can regulate chromosome segregation independent of centromere localization 16. CPC localization during metaphase is thought to rely on the intersection of two histone modifications at the centromere. Haspin kinase phosphorylates histone H3 on threonine 3 along chromosome arms and at centromeres, which is bound by Survivin 17,18. The kinetochore-localized kinase Bub1 phosphorylates histone H2A on threonine 120 at pericentromeric chromatin, which recruits Sgo1/2 18,19. Sgo1/2 can bind CDK1-phosphorylated Borealin, which also contributes to CPC localization to centromeres 18,20. Furthermore, Aurora B regulates pH3T3 by directly activating Haspin via phosphorylation. Also, both Aurora B and Mps1 regulate Bub1 recruitment to kinetochores 17,2123. We have analyzed CPC localization and function using a combination of Borealin structure-function studies, an FKBP-mediated dimerization system and kinase inhibitors to deplete known CPC receptors at the centromere. Our results 
suggest that monomeric CPC interacts transiently with the centromere via binding to pH3T3 while dimerization enhances centromere binding to provide optimal CPC function. Selective reduction of pH3T3 reveals a kinetochore proximal pool of CPC that partly co-localizes with pH2AT120, and depends on dimerization for localization. Additional experiments suggest that both the inner centromere and kinetochore-proximal pool of CPC contribute to activation of the SAC. However, reduced Aurora B activity is observed with mutations that either stabilize or destabilize the dimer in vitro 26. More likely, these mutations alter Borealin function by buy G5555 disrupting phosphorylation 26. Therefore, we created FKBP fusions using Borealin1-221 or Borealin1-110 where dimerization of FKBP fusion proteins can be 
induced using the small molecule AP20187 28. Adding AP20187 to HeLa M cells expressing the Borealin-FKBP fusions did not alter the total levels of the fusion proteins. Borealin-FKBP fusions proteins were expressed in taxol-arrested HeLa cells, which were then cultured in the presence or absence of the homo-dimerizing agent AP20187. Immunofluorescence was performed to assess localization of HA-tagged Borealin-FKBP fu.Ne mediators in response to chronic Gs activation in OBs were also indentified. All these regulated genes could be used for further functional studies. Biological validation of the role of these mediators may lead to new therapeutic targets for enhancing bone formation in osteoporosis and for reversing bone disease associated with excess Gs signaling.The tension-sensing system that regulates kinetochore-microtubule interactions depends on the Chromosomal Passenger Complex 6, composed of Borealin, Survivin, INCENP, and Aurora B 8. Prior to anaphase, the CPC localizes to inner centromeres, adjacent to sister kinetochores, to monitor inter-kinetochore tension. The prevailing model that explains the role of Aurora B in regulating the SAC posits that under low tension, Aurora B phosphorylates microtubule-binding kinetochore proteins resulting in reduced affinity for microtubules leading to dissociation of kinetochore-microtubule interactions 1014. As chromosomes become bi-oriented and sister kinetochores are under high tension, Aurora B is spatially separated from the kinetochore and can no longer destabilize kinetochoremicrotubule interactions. According to this spatial PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19850363 gradient model, inner centromere localization of the CPC is paramount for error correction 15. In yeast, however, INCENP can regulate chromosome segregation independent of centromere localization 16. CPC localization during metaphase is thought to rely on the intersection of two histone modifications at the centromere. Haspin kinase phosphorylates histone H3 on threonine 3 along chromosome arms and at centromeres, which is bound by Survivin 17,18. The kinetochore-localized kinase Bub1 phosphorylates histone H2A on threonine 120 at pericentromeric chromatin, which recruits Sgo1/2 18,19. Sgo1/2 can bind CDK1-phosphorylated Borealin, which also contributes to CPC localization to centromeres 18,20. Furthermore, Aurora B regulates pH3T3 by directly activating Haspin via phosphorylation. Also, both Aurora B and Mps1 regulate Bub1 recruitment to kinetochores 17,2123. We have analyzed CPC localization and function using a combination of Borealin structure-function studies, an FKBP-mediated dimerization system and kinase inhibitors to deplete known CPC receptors at the centromere. Our results suggest that monomeric CPC interacts transiently with the centromere via binding to pH3T3 while dimerization enhances centromere binding to provide optimal CPC function. Selective reduction of pH3T3 reveals a kinetochore proximal pool of CPC that partly co-localizes with pH2AT120, and depends on dimerization for localization. Additional experiments suggest that both the inner centromere and kinetochore-proximal pool of CPC contribute to activation of the SAC. However, reduced Aurora B activity is observed with mutations that either stabilize or destabilize the dimer in vitro 26. More likely, these mutations alter Borealin function by disrupting phosphorylation 26. Therefore, we created FKBP fusions using Borealin1-221 or Borealin1-110 where dimerization of FKBP fusion proteins can be induced using the small molecule AP20187 28. Adding AP20187 to HeLa M cells expressing the Borealin-FKBP fusions did not alter the total levels of the fusion proteins. Borealin-FKBP fusions proteins were expressed in taxol-arrested HeLa cells, which were then cultured in the presence or absence of the homo-dimerizing agent AP20187. Immunofluorescence was performed to assess localization of HA-tagged Borealin-FKBP fu.