IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues.
Phosphatidylinositol phosphate kinases (PIPKs) are lipid kinases that generate phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a critical lipid signaling molecule that regulates diverse cellular functions, including the activities of membrane channels and transporters. IRBIT (IP3R-binding protein...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2015-01-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4624786?pdf=render |
| _version_ | 1818361406518460416 |
|---|---|
| author | Hideaki Ando Matsumi Hirose Laura Gainche Katsuhiro Kawaai Benjamin Bonneau Takeshi Ijuin Toshiki Itoh Tadaomi Takenawa Katsuhiko Mikoshiba |
| author_facet | Hideaki Ando Matsumi Hirose Laura Gainche Katsuhiro Kawaai Benjamin Bonneau Takeshi Ijuin Toshiki Itoh Tadaomi Takenawa Katsuhiko Mikoshiba |
| author_sort | Hideaki Ando |
| collection | DOAJ |
| description | Phosphatidylinositol phosphate kinases (PIPKs) are lipid kinases that generate phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a critical lipid signaling molecule that regulates diverse cellular functions, including the activities of membrane channels and transporters. IRBIT (IP3R-binding protein released with inositol 1,4,5-trisphosphate) is a multifunctional protein that regulates diverse target proteins. Here, we report that IRBIT forms signaling complexes with members of the PIPK family. IRBIT bound to all PIPK isoforms in heterologous expression systems and specifically interacted with PIPK type Iα (PIPKIα) and type IIα (PIPKIIα) in mouse cerebellum. Site-directed mutagenesis revealed that two conserved catalytic aspartate residues of PIPKIα and PIPKIIα are involved in the interaction with IRBIT. Furthermore, phosphatidylinositol 4-phosphate, Mg2+, and/or ATP interfered with the interaction, suggesting that IRBIT interacts with catalytic cores of PIPKs. Mutations of phosphorylation sites in the serine-rich region of IRBIT affected the selectivity of its interaction with PIPKIα and PIPKIIα. The structural flexibility of the serine-rich region, located in the intrinsically disordered protein region, is assumed to underlie the mechanism of this interaction. Furthermore, in vitro binding experiments and immunocytochemistry suggest that IRBIT and PIPKIα interact with the Na+/HCO3- cotransporter NBCe1-B. These results suggest that IRBIT forms signaling complexes with PIPKIα and NBCe1-B, whose activity is regulated by PI(4,5)P2. |
| first_indexed | 2024-12-13T21:16:11Z |
| format | Article |
| id | doaj.art-112134259ee342e782b7d5aa18f05ee1 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-13T21:16:11Z |
| publishDate | 2015-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-112134259ee342e782b7d5aa18f05ee12022-12-21T23:31:13ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-011010e014156910.1371/journal.pone.0141569IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues.Hideaki AndoMatsumi HiroseLaura GaincheKatsuhiro KawaaiBenjamin BonneauTakeshi IjuinToshiki ItohTadaomi TakenawaKatsuhiko MikoshibaPhosphatidylinositol phosphate kinases (PIPKs) are lipid kinases that generate phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a critical lipid signaling molecule that regulates diverse cellular functions, including the activities of membrane channels and transporters. IRBIT (IP3R-binding protein released with inositol 1,4,5-trisphosphate) is a multifunctional protein that regulates diverse target proteins. Here, we report that IRBIT forms signaling complexes with members of the PIPK family. IRBIT bound to all PIPK isoforms in heterologous expression systems and specifically interacted with PIPK type Iα (PIPKIα) and type IIα (PIPKIIα) in mouse cerebellum. Site-directed mutagenesis revealed that two conserved catalytic aspartate residues of PIPKIα and PIPKIIα are involved in the interaction with IRBIT. Furthermore, phosphatidylinositol 4-phosphate, Mg2+, and/or ATP interfered with the interaction, suggesting that IRBIT interacts with catalytic cores of PIPKs. Mutations of phosphorylation sites in the serine-rich region of IRBIT affected the selectivity of its interaction with PIPKIα and PIPKIIα. The structural flexibility of the serine-rich region, located in the intrinsically disordered protein region, is assumed to underlie the mechanism of this interaction. Furthermore, in vitro binding experiments and immunocytochemistry suggest that IRBIT and PIPKIα interact with the Na+/HCO3- cotransporter NBCe1-B. These results suggest that IRBIT forms signaling complexes with PIPKIα and NBCe1-B, whose activity is regulated by PI(4,5)P2.http://europepmc.org/articles/PMC4624786?pdf=render |
| spellingShingle | Hideaki Ando Matsumi Hirose Laura Gainche Katsuhiro Kawaai Benjamin Bonneau Takeshi Ijuin Toshiki Itoh Tadaomi Takenawa Katsuhiko Mikoshiba IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues. PLoS ONE |
| title | IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues. |
| title_full | IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues. |
| title_fullStr | IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues. |
| title_full_unstemmed | IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues. |
| title_short | IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues. |
| title_sort | irbit interacts with the catalytic core of phosphatidylinositol phosphate kinase type iα and iiα through conserved catalytic aspartate residues |
| url | http://europepmc.org/articles/PMC4624786?pdf=render |
| work_keys_str_mv | AT hideakiando irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT matsumihirose irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT lauragainche irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT katsuhirokawaai irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT benjaminbonneau irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT takeshiijuin irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT toshikiitoh irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT tadaomitakenawa irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues AT katsuhikomikoshiba irbitinteractswiththecatalyticcoreofphosphatidylinositolphosphatekinasetypeiaandiiathroughconservedcatalyticaspartateresidues |