5tua

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structure of a Na+-selective mutant of two-pore channel from Arabidopsis thaliana AtTPC1structure of a Na+-selective mutant of two-pore channel from Arabidopsis thaliana AtTPC1

Structural highlights

5tua is a 1 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 3.3Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TPC1_ARATH Functions as a voltage-gated inward-rectifying Ca(2+) channel (VDCC) across the vacuole membrane. Is one of the essential components of the slow vacuolar (SV) channel. Acts as the major ROS-responsive Ca(2+) channel and is the possible target of Al-dependent inhibition. Involved in the regulation of germination and stomatal movement.[1] [2]

Publication Abstract from PubMed

Organellar two-pore channels (TPCs) contain two copies of a Shaker-like six-transmembrane (6-TM) domain in each subunit and are ubiquitously expressed in plants and animals. Interestingly, plant and animal TPCs share high sequence similarity in the filter region, yet exhibit drastically different ion selectivity. Plant TPC1 functions as a nonselective cation channel on the vacuole membrane, whereas mammalian TPC channels have been shown to be endo/lysosomal Na+-selective or Ca2+-release channels. In this study, we performed systematic characterization of the ion selectivity of TPC1 from Arabidopsis thaliana (AtTPC1) and compared its selectivity with the selectivity of human TPC2 (HsTPC2). We demonstrate that AtTPC1 is selective for Ca2+ over Na+, but nonselective among monovalent cations (Li+, Na+, and K+). Our results also confirm that HsTPC2 is a Na+-selective channel activated by phosphatidylinositol 3,5-bisphosphate. Guided by our recent structure of AtTPC1, we converted AtTPC1 to a Na+-selective channel by mimicking the selectivity filter of HsTPC2 and identified key residues in the TPC filters that differentiate the selectivity between AtTPC1 and HsTPC2. Furthermore, the structure of the Na+-selective AtTPC1 mutant elucidates the structural basis for Na+ selectivity in mammalian TPCs.

Tuning the ion selectivity of two-pore channels.,Guo J, Zeng W, Jiang Y Proc Natl Acad Sci U S A. 2017 Jan 17. pii: 201616191. doi:, 10.1073/pnas.1616191114. PMID:28096396[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Kawano T, Kadono T, Fumoto K, Lapeyrie F, Kuse M, Isobe M, Furuichi T, Muto S. Aluminum as a specific inhibitor of plant TPC1 Ca2+ channels. Biochem Biophys Res Commun. 2004 Nov 5;324(1):40-5. PMID:15464979 doi:http://dx.doi.org/S0006-291X(04)02051-0
  2. Peiter E, Maathuis FJ, Mills LN, Knight H, Pelloux J, Hetherington AM, Sanders D. The vacuolar Ca2+-activated channel TPC1 regulates germination and stomatal movement. Nature. 2005 Mar 17;434(7031):404-8. PMID:15772667 doi:http://dx.doi.org/nature03381
  3. Guo J, Zeng W, Jiang Y. Tuning the ion selectivity of two-pore channels. Proc Natl Acad Sci U S A. 2017 Jan 17. pii: 201616191. doi:, 10.1073/pnas.1616191114. PMID:28096396 doi:http://dx.doi.org/10.1073/pnas.1616191114

5tua, resolution 3.30Å

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