PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts
Protocadherin-7 (Pcdh7) is a member of the non-clustered protocadherin δ1 subgroup of the cadherin superfamily. Pcdh7 has been revealed to control osteoclast differentiation by regulating Rho-family small GTPases, RhoA and Rac1, through its intracellular SET binding domain. However, the mechanisms b...
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MDPI AG
2023-07-01
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| author | Hyunsoo Kim Noriko Takegahara Yongwon Choi |
| author_facet | Hyunsoo Kim Noriko Takegahara Yongwon Choi |
| author_sort | Hyunsoo Kim |
| collection | DOAJ |
| description | Protocadherin-7 (Pcdh7) is a member of the non-clustered protocadherin δ1 subgroup of the cadherin superfamily. Pcdh7 has been revealed to control osteoclast differentiation by regulating Rho-family small GTPases, RhoA and Rac1, through its intracellular SET binding domain. However, the mechanisms by which small GTPases are regulated downstream of Pcdh7 remain unclear. Here, we demonstrate that protein phosphatase 2A (PP2A)-mediated dephosphorylation of Glycogen synthase kinase-3β (GSK3β) is required for Pcdh7-dependent activation of RhoA during osteoclast differentiation. Pcdh7-deficient (Pcdh7<sup>−/−</sup>) cells showed impaired PP2A activity, despite their normal expression of PP2A. GSK3β, whose activity is regulated by its inhibitory phosphorylation at Ser9, was dephosphorylated during osteoclast differentiation in a Pcdh7-dependent manner. Inhibition of protein phosphatase by okadaic acid reduced dephosphorylation of GSK3β in Pcdh7<sup>+/+</sup> cells, while activation of PP2A by DT−061 rescued impaired dephosphorylation of GSK3β in Pcdh7<sup>−/−</sup> cells. Inhibition of GSK3β by AR−A014418 inhibited RANKL-induced RhoA activation and osteoclast differentiation in Pcdh7<sup>+/+</sup> cells. On the other hand, DT-061 treatment rescued impaired RhoA activation and RANKL-induced osteoclast differentiation in Pcdh7<sup>−/−</sup> cells. Taken together, these results demonstrate that PP2A dephosphorylates GSK3β and thereby activates it in a Pcdh7-dependent manner, which is required for activation of small GTPase RhoA and proper osteoclast differentiation. |
| first_indexed | 2024-03-11T00:29:03Z |
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| language | English |
| last_indexed | 2024-03-11T00:29:03Z |
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| spelling | doaj.art-146f6c03a1c4485184e4ca0a207b02fd2023-11-18T22:45:02ZengMDPI AGCells2073-44092023-07-011215196710.3390/cells12151967PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in OsteoclastsHyunsoo Kim0Noriko Takegahara1Yongwon Choi2Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USADepartment of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USADepartment of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USAProtocadherin-7 (Pcdh7) is a member of the non-clustered protocadherin δ1 subgroup of the cadherin superfamily. Pcdh7 has been revealed to control osteoclast differentiation by regulating Rho-family small GTPases, RhoA and Rac1, through its intracellular SET binding domain. However, the mechanisms by which small GTPases are regulated downstream of Pcdh7 remain unclear. Here, we demonstrate that protein phosphatase 2A (PP2A)-mediated dephosphorylation of Glycogen synthase kinase-3β (GSK3β) is required for Pcdh7-dependent activation of RhoA during osteoclast differentiation. Pcdh7-deficient (Pcdh7<sup>−/−</sup>) cells showed impaired PP2A activity, despite their normal expression of PP2A. GSK3β, whose activity is regulated by its inhibitory phosphorylation at Ser9, was dephosphorylated during osteoclast differentiation in a Pcdh7-dependent manner. Inhibition of protein phosphatase by okadaic acid reduced dephosphorylation of GSK3β in Pcdh7<sup>+/+</sup> cells, while activation of PP2A by DT−061 rescued impaired dephosphorylation of GSK3β in Pcdh7<sup>−/−</sup> cells. Inhibition of GSK3β by AR−A014418 inhibited RANKL-induced RhoA activation and osteoclast differentiation in Pcdh7<sup>+/+</sup> cells. On the other hand, DT-061 treatment rescued impaired RhoA activation and RANKL-induced osteoclast differentiation in Pcdh7<sup>−/−</sup> cells. Taken together, these results demonstrate that PP2A dephosphorylates GSK3β and thereby activates it in a Pcdh7-dependent manner, which is required for activation of small GTPase RhoA and proper osteoclast differentiation.https://www.mdpi.com/2073-4409/12/15/1967osteoclastsPcdh7PP2AGSK3βRhoAdifferentiation |
| spellingShingle | Hyunsoo Kim Noriko Takegahara Yongwon Choi PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts Cells osteoclasts Pcdh7 PP2A GSK3β RhoA differentiation |
| title | PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts |
| title_full | PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts |
| title_fullStr | PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts |
| title_full_unstemmed | PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts |
| title_short | PP2A-Mediated GSK3β Dephosphorylation Is Required for Protocadherin-7-Dependent Regulation of Small GTPase RhoA in Osteoclasts |
| title_sort | pp2a mediated gsk3β dephosphorylation is required for protocadherin 7 dependent regulation of small gtpase rhoa in osteoclasts |
| topic | osteoclasts Pcdh7 PP2A GSK3β RhoA differentiation |
| url | https://www.mdpi.com/2073-4409/12/15/1967 |
| work_keys_str_mv | AT hyunsookim pp2amediatedgsk3bdephosphorylationisrequiredforprotocadherin7dependentregulationofsmallgtpaserhoainosteoclasts AT norikotakegahara pp2amediatedgsk3bdephosphorylationisrequiredforprotocadherin7dependentregulationofsmallgtpaserhoainosteoclasts AT yongwonchoi pp2amediatedgsk3bdephosphorylationisrequiredforprotocadherin7dependentregulationofsmallgtpaserhoainosteoclasts |