CHST10 Human

What is CHST10 and what is its primary enzymatic function?

CHST10 (Carbohydrate Sulfotransferase 10) is an enzyme that transfers sulfate to glucuronic acid to form the HNK-1 antigen carried by glycoproteins and glycolipids in neurons and natural killer (NK) cells . Beyond this well-established function, research has demonstrated that CHST10 also sulfates glucuronidated steroid hormones, including estrogen and testosterone . This dual functionality positions CHST10 at an interesting intersection between neurological and endocrinological processes, making it a compelling target for multidisciplinary research.

What structural characteristics define human CHST10?

Human CHST10 protein spans amino acids Pro32-Asn356, as indicated by recombinant protein specifications . The protein contains critical catalytic domains, including the RDP sequence found in exon 5, which is essential for enzymatic function . For research applications, recombinant CHST10 is often produced with a C-terminal 6-His tag to facilitate purification and detection . Understanding these structural elements is crucial for designing experiments involving site-directed mutagenesis or structure-function analyses.

What expression patterns of CHST10 are observed across human tissues?

CHST10 is ubiquitously expressed in various tissues, though with notable variation in expression levels . It shows particularly high expression in neuronal cells where the HNK-1 antigen is prominently found . When designing tissue-specific studies, researchers should consider this differential expression pattern and select appropriate experimental models that reflect the physiological context of interest.

How does CHST10 influence neuronal function through HNK-1 synthesis?

CHST10 synthesizes the HNK-1 antigen on neural cell adhesion proteins and glycolipids, which is thought to modulate cell adhesion processes critical for neuronal development and function . Studies with Chst10-deficient mice have revealed impacts on synaptic transmission and long-term potentiation, resulting in impaired spatial learning . When investigating CHST10's neurological roles, researchers should employ both electrophysiological approaches to assess synaptic function and behavioral assays to evaluate cognitive outcomes, as these complementary methods can provide insights into both cellular mechanisms and functional consequences.

What methodologies are most effective for studying CHST10's neurobiological effects?

While the search results don't provide extensive details on neural assessment techniques, immunohistochemistry using anti-HNK-1 antibody has been successfully employed to confirm the elimination of HNK-1 antigen in Chst10 null mice . For comprehensive neurobiological investigation, researchers should consider:

• Electrophysiological recordings to quantify changes in basal synaptic transmission and long-term potentiation

• Morris water maze or other spatial learning paradigms to assess cognitive impacts

• Detailed morphological analysis of neuronal structures using high-resolution microscopy

• Molecular characterization of HNK-1-bearing adhesion molecules in different neural circuits

These approaches can collectively provide a multidimensional view of CHST10's neurobiological functions.

How might CHST10 connect endocrine signaling to neuronal function?

An intriguing hypothesis emerging from CHST10 research suggests that the sulfation modifications catalyzed by this enzyme may establish a functional link between steroid hormones and neuronal activation in mammals . This possibility is supported by observations that sulfated steroids can bind to vomeronasal receptors and function as pheromones in mice and fish . Researchers investigating this potential neuroendocrine axis should design experiments that:

• Track the fate of CHST10-modified steroids in neural tissues

• Evaluate the binding of these modified hormones to neural receptors

• Assess neuronal activation patterns in response to sulfated hormones

• Compare these responses between wild-type and Chst10-deficient models

This research direction could reveal novel mechanisms of neuroendocrine communication.

How does CHST10 regulate steroid hormone activity?

CHST10 regulates steroid hormones by adding sulfate groups to their glucuronidated forms, effectively creating doubly-conjugated hormones . Research using Chst10-deficient mice has revealed that this sulfation likely serves as an inactivation mechanism, as Chst10-null female mice exhibited higher serum estrogen levels than wild-type counterparts . Enzymatic activity assays combined with structural analysis by HPLC and mass spectrometry confirmed that CHST10 sulfates glucuronidated estrogen, testosterone, and other steroid hormones .

Importantly, estrogen-response element reporter assays demonstrated that CHST10-modified estrogen likely cannot bind to its receptor, providing a molecular mechanism for this inactivation . For researchers studying hormone regulation, this suggests that CHST10 should be considered as part of the complex enzymatic network that modulates hormone bioavailability.

What reproductive phenotypes result from CHST10 deficiency?

In mouse models, Chst10 deficiency results in subfertility in both males and females . The phenotypic characteristics in female Chst10-/- mice include:

• Enlarged uteri with thickened uterine endometrium at the pro-estrus stage

• Elevated serum estrogen levels

• Disrupted hormonal cycles

• Reduced reproductive success (5.4 pups/litter compared to 8.11 pups/litter in crosses between Chst10+/- mice)

These findings indicate that CHST10 plays a crucial role in maintaining proper hormonal balance for optimal reproductive function. Researchers investigating reproductive biology should consider CHST10's role alongside better-characterized hormone-modifying enzymes.

What experimental approaches best capture CHST10's impact on hormone regulation?

Several complementary methods have proven effective for studying CHST10's role in hormone regulation:

• Targeted gene disruption: Disruption of exon 5 (containing the catalytic RDP domain) by homologous recombination can generate Chst10-deficient models

• Radioimmunoassay: This technique allows precise quantification of serum hormone levels across estrous cycle stages

• HPLC and mass spectrometry: These analytical methods enable identification and characterization of CHST10-modified steroid hormones

• Estrogen-response element reporter assays: These functional assays determine whether modified hormones can activate their receptors

• Histological analysis: Microscopic examination reveals morphological changes in reproductive tissues that reflect altered hormone activity

Researchers should employ multiple approaches to build a comprehensive understanding of CHST10's hormonal effects.

How is CHST10 regulated in melanoma and what are the functional implications?

In S91 murine melanoma cells, CHST10 is regulated by retinoic acid (RA) through activation of retinoic acid receptor gamma (RARγ) . DNA microarray analysis combined with RAR isoform-specific agonists identified CHST10 as a novel RARγ target gene . The RARγ-inducible CHST10 promoter contains two atypical, independently functioning RA response elements in a 425 bp region that is bound specifically by RARγ but not by RARα or RARβ .

This RARγ-specific regulation explains why melanoma differentiation is mediated by RARγ but not other RAR isoforms . Functionally, three-dimensional cell culture migration assays suggest that CHST10 acts as a suppressor of invasiveness, but not proliferation, in melanoma cells . This suppressive role may relate to CHST10's function in synthesizing the HNK-1 antigen, which modulates cell adhesion properties .

What experimental models are most effective for studying CHST10 in oncology?

Based on the search results, effective experimental models for studying CHST10 in cancer contexts include:

• S91 murine melanoma cells: This model has proven valuable for studying RA-induced growth arrest and differentiation

• Human melanoma cell lines: These can verify the relevance of findings to human disease

• Three-dimensional cell culture migration assays: These provide functional assessment of invasiveness

• DNA microarrays combined with receptor-specific agonists: This approach identifies target genes and regulatory mechanisms

When designing oncology studies involving CHST10, researchers should consider which aspects of cancer biology (differentiation, invasion, adhesion) they wish to investigate and select appropriate models accordingly.

How might CHST10 modulation be exploited therapeutically in cancer?

The research suggests that "induction of CHST10 by RARγ-activating retinoids may present a novel therapeutic strategy to inhibit invasiveness in a subset of melanoma patients" . To explore this therapeutic potential, researchers should:

• Identify biomarkers that predict which melanoma subtypes would respond to CHST10 induction

• Develop selective RARγ agonists with optimal pharmacokinetic properties

• Investigate potential synergies between CHST10 induction and established melanoma treatments

• Establish robust in vivo models to assess the impact on metastatic potential

This approach could lead to novel differentiation therapy strategies for melanoma.

What assay systems accurately measure CHST10 enzymatic activity?

The search results describe a specific assay procedure for measuring CHST10 enzymatic activity :

This assay system enables quantitative measurement of CHST10's sulfotransferase activity. Researchers should optimize substrate concentrations and reaction conditions for their specific experimental questions, and consider including appropriate controls to account for background sulfotransferase activity.

How can CHST10 knockout models be generated and validated?

Based on the search results, effective CHST10 knockout models can be generated through targeted disruption of critical exons using homologous recombination . The specific approach includes:

• Constructing a targeting vector to disrupt exon 5, which contains the critical RDP catalytic domain sequence

• Selecting homologously recombined ES clones by Southern hybridization

• Distinguishing targeted (3.8 kb) from wild-type (7.4 kb) alleles by EcoRI digestion of genomic DNA

• Confirming genotypes by PCR using primers specific to:

  • The Neo insertion (5'-primer in Neo)

  • Common sequence (3'-primer in the common sequence)

  • Deleted sequence (5'-primer in deleted sequence)

Validation should include:

• Confirming elimination of the HNK-1 antigen by immunohistochemistry using anti-HNK-1 antibody

• Assessing expected phenotypic changes in reproductive or neurological systems

Researchers should consider whether complete knockout or conditional tissue-specific approaches are most appropriate for their specific research questions.

What considerations are important when using recombinant CHST10 in experiments?

When using recombinant CHST10 in experiments, researchers should consider:

• Protein formulation: Recombinant human CHST10 is supplied as a 0.2 μm filtered solution in Tris and NaCl

• Storage conditions: The protein should be stored to avoid repeated freeze-thaw cycles

• Carrier protein presence: CHST10 may be available with or without bovine serum albumin (BSA); carrier-free versions are recommended for applications where BSA could interfere

• Purity requirements: For enzyme activity studies, high purity (>95%) recombinant protein should be used to minimize interference from contaminants

• Appropriate controls: Include controls to account for any effects of purification tags or other modifications used in the recombinant protein

These considerations ensure reliable and reproducible results when working with recombinant CHST10.

How can contradictory findings regarding CHST10 function be reconciled?

The search results reveal a discrepancy between different Chst10 knockout mouse lines. One study reported that mice with mutations in the second exon of Chst10 were viable and fertile but showed impaired synaptic transmission and long-term memory deficits . In contrast, another study found subfertility in their Chst10 knockout mice .

The authors suggest this discrepancy might be due to their targeting construct potentially producing a fragment of Chst10 protein (translated from exons 1-4) that could function as a dominant negative for other sulfotransferases, resulting in stronger phenotypes .

To reconcile such contradictory findings, researchers should:

• Compare knockout strategies in detail, particularly the exact genomic regions targeted

• Assess whether partial protein fragments might have dominant-negative effects

• Consider genetic background differences that might influence phenotypic outcomes

• Employ multiple knockdown/knockout approaches (CRISPR, siRNA, antisense) to validate findings

• Use tissue-specific conditional knockout approaches to isolate effects in specific systems

This methodical approach can help resolve apparently contradictory results in the literature.

What are the potential interactions between CHST10 and other steroid-modifying enzymes?

The search results suggest that CHST10 may interact with or be regulated alongside other steroid-modifying enzymes . When intravenously injected estradiol (E2) was not modified in Chst10-/- mice, the researchers concluded that "activities of conjugation enzymes other than Chst10 are also suppressed in Chst10 null mice" .

The researchers note that future studies should define "whether steroid-modifying enzymes interact with one another or are regulated together" . To investigate these potential interactions, researchers could:

• Perform co-immunoprecipitation studies to identify physical interactions

• Use proximity ligation assays to detect close associations in cellular contexts

• Conduct transcriptomic analyses to identify co-regulated enzyme networks

• Employ metabolomics approaches to map the flux through steroid modification pathways

• Generate double or triple knockout models to identify functional redundancy or synergy

Understanding these enzymatic networks could reveal new regulatory mechanisms in steroid hormone metabolism.

How might CHST10's dual roles in neuronal and hormonal systems be integrated?

CHST10's functions in both neuronal HNK-1 synthesis and hormone modification suggest intriguing possibilities for neuroendocrine integration. The search results note that "expression of an SO3-GlcUA-terminal structure as an HNK-1 antigen in neurons together with the existence of a similar structural modification of sex steroid hormones suggest that this modification may have an unidentified endocrine function linking steroid hormones to neuronal activation in mammals" .

To explore this potential neuroendocrine axis, advanced research approaches might include:

• Tracing the fate of CHST10-modified steroids in neural tissues using radiolabeled precursors

• Identifying potential receptors for sulfated-glucuronidated hormones in neural tissues

• Investigating whether these modified hormones cross the blood-brain barrier

• Comparing neural responses to native versus CHST10-modified hormones

• Examining the impact of reproductive or hormonal challenges on HNK-1 expression patterns

This research direction could reveal novel mechanisms of communication between the endocrine and nervous systems, with potential implications for understanding conditions affecting both systems.