7dsx

Structural highlights

Function

CHP1_HUMAN Calcium-binding protein involved in different processes such as regulation of vesicular trafficking, plasma membrane Na(+)/H(+) exchanger and gene transcription. Involved in the constitutive exocytic membrane traffic. Mediates the association between microtubules and membrane-bound organelles of the endoplasmic reticulum and Golgi apparatus and is also required for the targeting and fusion of transcytotic vesicles (TCV) with the plasma membrane. Functions as an integral cofactor in cell pH regulation by controlling plasma membrane-type Na(+)/H(+) exchange activity. Affects the pH sensitivity of SLC9A1/NHE1 by increasing its sensitivity at acidic pH. Required for the stabilization and localization of SLC9A1/NHE1 at the plasma membrane. Inhibits serum- and GTPase-stimulated Na(+)/H(+) exchange. Plays a role as an inhibitor of ribosomal RNA transcription by repressing the nucleolar UBF1 transcriptional activity. May sequester UBF1 in the nucleoplasm and limit its translocation to the nucleolus. Associates to the ribosomal gene promoter. Acts as a negative regulator of the calcineurin/NFAT signaling pathway. Inhibits NFAT nuclear translocation and transcriptional activity by suppressing the calcium-dependent calcineurin phosphatase activity. Also negatively regulates the kinase activity of the apoptosis-induced kinase STK17B. Inhibits both STK17B auto- and substrate-phosphorylations in a calcium-dependent manner.^{[1] [2] [3] [4]}

References

1. ↑ Lin X, Barber DL. A calcineurin homologous protein inhibits GTPase-stimulated Na-H exchange. Proc Natl Acad Sci U S A. 1996 Oct 29;93(22):12631-6. PMID:8901634
2. ↑ Lin X, Sikkink RA, Rusnak F, Barber DL. Inhibition of calcineurin phosphatase activity by a calcineurin B homologous protein. J Biol Chem. 1999 Dec 17;274(51):36125-31. PMID:10593895
3. ↑ Pang T, Su X, Wakabayashi S, Shigekawa M. Calcineurin homologous protein as an essential cofactor for Na+/H+ exchangers. J Biol Chem. 2001 May 18;276(20):17367-72. Epub 2001 Feb 28. PMID:11350981 doi:http://dx.doi.org/10.1074/jbc.M100296200
4. ↑ Pang T, Hisamitsu T, Mori H, Shigekawa M, Wakabayashi S. Role of calcineurin B homologous protein in pH regulation by the Na+/H+ exchanger 1: tightly bound Ca2+ ions as important structural elements. Biochemistry. 2004 Mar 30;43(12):3628-36. PMID:15035633 doi:http://dx.doi.org/10.1021/bi0360004