Disease relevance of Sts

• Mice heterozygous at two pseudoautosomal alleles, the steroid sulfatase gene and the Mov-15 provirus marker, were crossed [1].
• IL-1beta has been shown to play a key role in contact hypersensitivity; we show that ASC- and NALP3-deficient mice also demonstrate an impaired contact hypersensitivity response to the hapten trinitrophenylchloride [2].
• Rate of proliferation and amino acid transport were assessed in simian virus 40 (SV40)-transformed 3T3 cells by measurements of growth rate quotient and L-serine uptake via System ASC, respectively [3].
• We have studied the role of ASC in the host defense against the intracellular pathogen Listeria monocytogenes [4].
• Recent studies of the epidermis in patients with recessive X-linked ichthyosis indicate that cholesterol sulfate is an important endogenous substrate for steroid sulfatase in the stratum corneum [5].

High impact information on Sts

• The steroid sulfatase functional gene (STS) maps to the distal short arm of the X chromosome proximal to XG [6].
• The combined results indicate that the murine steroid sulfatase locus is not dosage compensated and is not subject to X-inactivation [7].
• In this study we compared steroid sulfatase levels in XO, XX, and XY mice and carried out a clonal analysis in fibroblast cell cultures from mice heterozygous for the steroid sulfatase deficiency gene and heterozygous at the X-linked electrophoretic phosphoglycerate kinase locus [7].
• In addition, the steroid sulfatase enzyme (STS) is putatively linked to fear reactivity by an effect on GABAA receptors via the action of neurosteroids [8].
• It is concluded that in B16F1 cells BPA is transported by L and presumably ASC (alanine, serine, and cysteine) transport systems, and that boron uptake can be effectively stimulated by L-tyrosine preloading [9].

Chemical compound and disease context of Sts

• It was concluded that neural amino acid transport pathways (specifically A, L, ASC, and beta) do not participate in the transmembrane transfer of L-thyroxine into Ehrlich ascites cells [10].
• Threonine appears to be a specific substrate for a Na+-dependent amino acid transport system similar to system ASC of the HTC hepatoma cell [11].

Biological context of Sts

• Thus, in mouse, functional Sts genes are present in the pseudoautosomal region of both the X and Y chromosomes [12].
• If the rate of recombination in the pseudoautosomal region in male mice is equivalent to that in man and thus 7-10X higher than normal, then our data suggest that the distance between Sts and Sxr (or the telomere of the Y) is approximately 100-200 kb in length [12].
• A molecular candidate for this effect is Steroid sulfatase (Sts) as this is located in the pseudoautosomal region (PAR) of the X-chromosome and consequently is normally biallelically expressed [8].
• Dosage studies and the inheritance pattern of the gene for steroid sulfatase (Sts) in the mouse have previously provided indirect evidence for a functional Y-linked allele which recombines obligatorily with its X-linked allele in male meiosis [13].
• Final proof that the mouse Sts locus can be subject to the X-inactivation process was provided by the observation that XX females had STS levels that were only slightly (20%) higher than those of XO females [14].

Anatomical context of Sts

• We have purified steroid sulfatase approximately 30-fold from mouse liver microsomes and its properties have been investigated [15].
• Secretion of IL-1beta in response to lipopeptide, a TLR2 agonist, was greatly reduced in ASC-null macrophages and was abolished in TLR2-deficient macrophages [4].
• Because nonsaturable transport of glutamine appeared negligible, and system L transport of glutamine was suppressed in the presence of Na+, low-affinity system ASC transport may be the major route of export of glutamine from astrocytes [16].
• While proline transport in most mammalian cells is largely accomplished through System A, it is about equally divided between Systems A and ASC in OC15 cells, and System A does not contribute at all to proline transport by F9 cells, an EC cell line with limited developmental potential [17].
• Glutamine transport across the cell membranes of a variety of mammalian tissues is mediated by at least four transport systems: a sodium-independent system L, and sodium-dependent systems A, ASC and N, the latter occurring in different tissue-specific variants [18].

Associations of Sts with chemical compounds

• The murine steroid sulfatase (mSTS) is a microsomal enzyme, important in steroid metabolism [15].
• The uptake of proline and leucine by membrane transport Systems A, ASC, and L was discriminated on the basis of their sodium dependency and sensitivity to the system-specific amino acid analogs 2-(methylamino)-isobutyric acid (MeAIB) for System A and 2-amino-(2,2,1)-heptane-2-carboxylic acid (BCH) for System L [19].
• L-Proline, 2-aminoisobutyric acid, and glycine were primarily taken up by system A; L-alanine and L-serine by system ASC; L-phenylalanine by system L; and L-lysine by system Ly+ in SV3T3 cells [20].
• Serine, a substrate of ASC uptake system, had negligible effects on cysteine uptake at 10-fold excess concentrations [21].
• L-Proline and L-serine were also preferential substrates of systems A and ASC, respectively, in 3T3 and SV3T3 revertant cells [20].

Other interactions of Sts

• Our data is in contrast to a recent report of a recombination frequency separating Sts and Sxr of as high as 6.2-9.8% [12].
• This showed that although Sts may cause alterations in GABAA subunit expression, these changes do not result in increased fear reactivity [8].
• Because the Y chromosome contributes little to cellular function, the stability of the Y chromosome in the tumors was assessed by polymerase chain reaction by examining three genes: Smcy and Sry on the short arm and Sts in the pseudoautosomal region of the long arm of the Y chromosome [22].
• Mammalian sex chromosomes. III. Activity of pseudoautosomal steroid sulfatase enzyme during spermatogenesis in Mus musculus [23].

Analytical, diagnostic and therapeutic context of Sts

• CONCLUSIONS: ASC and TOC can be used to prevent systemic UV-induced immunosuppression [24].
• The levels of ASC and TOC in the epidermis were determined by HPLC [24].
• At the highest dose, the response in the ASC-treated mice was no longer significantly different from that in the positive control group [24].

References