Reciprocal stabilization of ABL and TAZ regulates osteoblastogenesis through transcription factor RUNX2
Yoshinori Matsumoto, Jose La Rose, Oliver A. Kent, Melany J. Wagner, Masahiro Narimatsu, Aaron D. Levy, Mitchell H. Omar, Jiefei Tong, Jonathan R. Krieger, Emily Riggs, Yaryna Storozhuk, Julia Pasquale, Manuela Ventura, Behzad Yeganeh, Martin Post, Michael F. Moran, Marc D. Grynpas, Jeffrey L. Wrana, Giulio Superti-Furga, Anthony J. Koleske, Ann Marie Pendergast, Robert Rottapel
Yoshinori Matsumoto, Jose La Rose, Oliver A. Kent, Melany J. Wagner, Masahiro Narimatsu, Aaron D. Levy, Mitchell H. Omar, Jiefei Tong, Jonathan R. Krieger, Emily Riggs, Yaryna Storozhuk, Julia Pasquale, Manuela Ventura, Behzad Yeganeh, Martin Post, Michael F. Moran, Marc D. Grynpas, Jeffrey L. Wrana, Giulio Superti-Furga, Anthony J. Koleske, Ann Marie Pendergast, Robert Rottapel
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Research Article Bone biology Cell biology

Reciprocal stabilization of ABL and TAZ regulates osteoblastogenesis through transcription factor RUNX2

Abstract

Cellular identity in metazoan organisms is frequently established through lineage-specifying transcription factors, which control their own expression through transcriptional positive feedback, while antagonizing the developmental networks of competing lineages. Here, we have uncovered a distinct positive feedback loop that arises from the reciprocal stabilization of the tyrosine kinase ABL and the transcriptional coactivator TAZ. Moreover, we determined that this loop is required for osteoblast differentiation and embryonic skeletal formation. ABL potentiated the assembly and activation of the RUNX2-TAZ master transcription factor complex that is required for osteoblastogenesis, while antagonizing PPARγ-mediated adipogenesis. ABL also enhanced TAZ nuclear localization and the formation of the TAZ-TEAD complex that is required for osteoblast expansion. Last, we have provided genetic data showing that regulation of the ABL-TAZ amplification loop lies downstream of the adaptor protein 3BP2, which is mutated in the craniofacial dysmorphia syndrome cherubism. Our study demonstrates an interplay between ABL and TAZ that controls the mesenchymal maturation program toward the osteoblast lineage and is mechanistically distinct from the established model of lineage-specific maturation.

Authors

Yoshinori Matsumoto, Jose La Rose, Oliver A. Kent, Melany J. Wagner, Masahiro Narimatsu, Aaron D. Levy, Mitchell H. Omar, Jiefei Tong, Jonathan R. Krieger, Emily Riggs, Yaryna Storozhuk, Julia Pasquale, Manuela Ventura, Behzad Yeganeh, Martin Post, Michael F. Moran, Marc D. Grynpas, Jeffrey L. Wrana, Giulio Superti-Furga, Anthony J. Koleske, Ann Marie Pendergast, Robert Rottapel

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Figure 7

TAZ regulates ABL protein stability by competitive displacement of the ABL E3-ubiquitin ligase SMURF1.

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TAZ regulates ABL protein stability by competitive displacement of the A...
(A) HEK 293T cells were cotransfected with ABL, with or without the indicated HECT domain–containing E3-ligases. The specific E3-ligase transfected into cells is indicated at the top panel of Western blots (SMURF1, SMURF2, NEDD4-1, NEDD4-2, and ITCH; 0–0.5 μg/well). WCLs were probed with the indicated antibodies for Western blot analysis. (B) HEK293T cells cotransfected with the indicated constructs, with or without SMURF1 (WT or C710A mutant [CA]), were treated with 10 μM MG132 for 4 hours prior to collection of cell lysates. ABL immune complexes were probed with an anti-HA or anti-ABL antibody. (C) HEK293T cells were cotransfected with ABL, Myc-SMURF1 (C710A), and increasing amounts of the TAZ construct. ABL immune complexes were probed with an anti-Myc antibody. (D) HEK293T cells cotransfected with the indicated constructs were treated with 10 μM MG132 for 4 hours prior to collection of cell lysates. ABL immune complexes were probed with an anti-HA or anti-ABL antibody. (E) HEK293T cells were cotransfected with ABL and Myc-SMURF1 (C710A), with or without TAZ (WT or ΔWW). ABL immune complexes were probed with an anti-Myc antibody. (F) Primary murine osteoblasts from WT or Smurf1–/– (KO) mice were infected with shGFP or shABL and cultured in osteogenic medium. WCLs were probed with the indicated antibodies for Western blot analysis. (G) Osteoblasts in F were cultured in osteogenic medium and stained with alizarin red S solution. n = 3.