Annotations: 8TYU

High-resolution crystal structure of the SPX domain of XPR1 at 1.4 angstroms

External Resource: Annotation

Domain Annotation: ECOD Classification
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
B [auth A]	WD40	e8tyuA1	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: WD40	ECOD (v294.2)
A [auth B]	DNA_pol_lambd_f	e8tyuB01	A: beta barrels	X: cradle loop barrel	H: RIFT-related	T: acid protease	F: DNA_pol_lambd_f	ECOD (v294.2)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A [auth B], B [auth A]	PF03105	SPX domain (SPX)	SPX domain	We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhi ...	We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal [3]. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 Swiss:P17442 from Saccharomyces cerevisiae and NUC-2 Swiss:Q01317 from Neurospora crassa, are also members of this family [4,5]. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 [6] NUC-2 contains several ankyrin repeats Pfam:PF00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV) [1]. Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death [7]. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organisms [1,2,6,7]. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor [1].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A [auth B], B [auth A]	Solute carrier family 53 member 1	protein binding binding virus receptor activity exogenous protein binding ion binding inositol hexakisphosphate binding alcohol binding anion binding small molecule binding active transmembrane transporter activity transporter activity transmembrane transporter activity phosphate transmembrane transporter activity secondary active transmembrane transporter activity protein binding binding virus receptor activity exogenous protein binding ion binding inositol hexakisphosphate binding alcohol binding anion binding small molecule binding active transmembrane transporter activity transporter activity transmembrane transporter activity phosphate transmembrane transporter activity secondary active transmembrane transporter activity efflux transmembrane transporter activity	biological process involved in interspecies interaction between organisms response to stimulus response to other organism response to external stimulus response to external biotic stimulus response to virus response to biotic stimulus phosphate ion homeostasis intracellular phosphate ion homeostasis cellular homeostasis inorganic ion homeostasis chemical homeostasis homeostatic process intracellular chemical homeostasis biological process involved in interspecies interaction between organisms response to stimulus response to other organism response to external stimulus response to external biotic stimulus response to virus response to biotic stimulus phosphate ion homeostasis intracellular phosphate ion homeostasis cellular homeostasis inorganic ion homeostasis chemical homeostasis homeostatic process intracellular chemical homeostasis localization transport phosphate ion transport establishment of localization inorganic anion transport cellular response to stimulus cellular response to nutrient levels response to nutrient levels cellular response to phosphate starvation cellular response to stress response to stress cellular process response to starvation cellular response to starvation transmembrane transport phosphate ion transmembrane transport	cell periphery cellular anatomical structure plasma membrane membrane

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A [auth B], B [auth A]	IPR004331	SPX domain	Domain
A [auth B], B [auth A]	IPR004342	EXS, C-terminal	Domain

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
A [auth B], B [auth A]	: Q9UBH6	basal ganglia calcification, idiopathic, 6 basal ganglia disease basal ganglia calcification, idiopathic, 1 bilateral striopallidodentate calcinosis calcinosis primitive neuroectodermal tumor atypical teratoid rhabdoid tumor Creutzfeldt Jacob disease glioblastoma malignant ependymoma Microcalcification ovarian cancer ductal breast carcinoma in situ juvenile dermatomyositis malignant glioma basal ganglia calcification, idiopathic, 6 basal ganglia disease basal ganglia calcification, idiopathic, 1 bilateral striopallidodentate calcinosis calcinosis primitive neuroectodermal tumor atypical teratoid rhabdoid tumor Creutzfeldt Jacob disease glioblastoma malignant ependymoma Microcalcification ovarian cancer ductal breast carcinoma in situ juvenile dermatomyositis malignant glioma non-small cell lung carcinoma pancreatic intraductal papillary-mucinous neoplasm with low grade dysplasia medulloblastoma osteosarcoma

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