Recombinant Mouse Abhydrolase domain-containing protein 14A (Abhd14a)

What is the molecular structure and basic characteristics of recombinant Mouse Abhd14a?

Recombinant Mouse Abhydrolase domain-containing protein 14A (Abhd14a) is a protein with a molecular weight of approximately 27.9 kDa. When expressed in heterologous systems such as HEK293T cells, it is typically tagged with epitopes such as C-MYC/DDK to facilitate detection and purification. The protein belongs to the metabolic serine hydrolase family, which is characterized by specific conserved sequence motifs including a nucleophilic motif and an acyltransferase motif .

For optimal structural stability during storage and experiments, the purified recombinant protein is typically maintained in buffer conditions consisting of 25 mM Tris.HCl, pH 7.3, with 100 mM glycine and 10% glycerol . The protein purity when obtained from commercial sources is generally >80% as determined by SDS-PAGE and Coomassie blue staining techniques .

How does Abhd14a relate to other ABHD family proteins, particularly ABHD14B?

Abhd14a shares high sequence similarity with ABHD14B, which has led to challenges in functional annotation. Despite their similarity, these proteins have distinct functional properties. While ABHD14B has been identified as functioning as a lysine deacetylase (KDAC) in mammals, ABHD14A still lacks definitive functional annotation .

The high sequence similarity between these proteins has created issues in automated database annotations, where ABHD14A and ABHD14B are sometimes incorrectly assigned as the same enzyme. This misclassification can complicate functional studies and annotations across organisms. Recent bioinformatics coupled with biochemical experiments have identified key sequence determinants for both ABHD14A and ABHD14B that enable better classification and distinction between these closely related enzymes .

What expression patterns does Abhd14a demonstrate in different developmental stages and tissues?

Based on expression data from model organisms like Xenopus (frog), Abhd14a expression has been detected across multiple tissues including brain, pancreas, and in Keller explants. Expression spans developmental stages from NF stage 10.5 through to adult organisms .

RNA-Seq and EST transcriptome profiles have been established for Abhd14a in different species including Xenopus tropicalis and Xenopus laevis (both L and S forms). These profiles provide valuable baseline data for researchers interested in developmental expression patterns. The temporal and spatial expression patterns suggest potential roles in both embryonic development and mature tissue function, particularly in neural tissues .

What are the common synonyms and identifiers for Mouse Abhd14a in research databases?

When searching for Mouse Abhd14a in research databases, several synonyms and identifiers may be encountered:

• Synonyms: 1110013B16Rik, AW558221, Dorz1

• Transcript identifiers: NM_145919 (for transcript variant 2)

• Catalog numbers: Examples include TP503112-OR (from commercial suppliers like OriGene)

Using these alternative identifiers can be crucial for comprehensive literature searches and database queries when conducting research on this protein. Different nomenclature may be used in various research contexts or across different model organism databases.

What expression systems and purification methods are optimal for producing functional recombinant Mouse Abhd14a?

For expression of recombinant Mouse Abhd14a, mammalian expression systems, particularly HEK293T cells, have proven effective for producing functional protein . This system allows for proper folding and potential post-translational modifications that may be important for protein function.

The recommended purification approach includes:

• Expression with C-terminal epitope tags (C-MYC/DDK) to facilitate affinity purification

• Affinity chromatography using anti-tag antibodies

• Buffer optimization containing 25 mM Tris.HCl, pH 7.3, 100 mM glycine, and 10% glycerol to maintain stability

• Quality control by SDS-PAGE and Coomassie blue staining to confirm purity (>80%)

For functional studies, it's important to verify the activity of the purified protein using established biochemical assays such as activity-based protein profiling (ABPP) or substrate hydrolysis assays like those using pNP-acetate as a substrate surrogate, similar to methods employed for ABHD14B .

What are the most effective biochemical assays for characterizing Abhd14a catalytic activity?

Based on approaches used for the related ABHD14B, two complementary assays have proven particularly useful for characterizing enzymatic activity:

• Gel-based Activity-Based Protein Profiling (ABPP):

  • Uses activity-based probes like FP-rhodamine that react with the nucleophilic active site serine

  • Provides a qualitative readout of catalytic site accessibility and reactivity

  • Useful for comparing wild-type and mutant proteins or assessing inhibitor binding

• pNP-acetate hydrolysis assay:

  • Colorimetric substrate hydrolysis assay that provides a direct readout of catalytic activity

  • Quantitative measurement of the enzyme's ability to turn over an acetylated substrate surrogate

  • Effective for kinetic analyses and comparing relative activities of variants

These approaches could be adapted specifically for Abhd14a, with appropriate controls to establish baseline activities and verify assay specificity.

What bioinformatic approaches are useful for identifying conserved functional motifs in Abhd14a across species?

Several powerful bioinformatic approaches have been applied successfully to ABHD family proteins:

• PSI-BLAST searches: Conducting iterative searches using reference sequences (like human ABHD14A, RefSeq: NP_056222.2, Uniprot: Q9BUJ0) against non-redundant databases with defined expect thresholds (e.g., 0.00005) and maximum return limits (e.g., 5000 hits) .

• Motif identification: Analysis of sequence alignments to identify conserved motifs that may be indicative of catalytic function, such as nucleophilic motifs (e.g., SxSxS within specific sequence contexts) and acyltransferase motifs (e.g., HxxxxD within specific sequence contexts) .

• Phylogenetic analysis: Construction of evolutionary trees to understand relationships between ABHD14A sequences across different taxonomic groups, which can provide insights into functional conservation and specialization .

• Transmembrane domain prediction: Assessment of potential membrane association using specialized algorithms to predict protein localization .

These approaches collectively provide a comprehensive framework for understanding the evolutionary context and potential functional regions of Abhd14a.

What neurodevelopmental disorders have been associated with mutations in ABHD14A?

Recent studies have identified ABHD14A as a potential candidate gene for several neurodevelopmental disorders:

• Developmental Language Disorder (DLD): Whole exome sequencing of affected families has identified ABHD14A variants, including a rare missense variant (c.689T>G) and three splice-site variants (c.70-8C>T, c.282-25A>T, and c.282-10G>C) with low-frequency minor allele frequencies (<5%). These variants are predicted to be pathogenic, with the missense variant Leu230Arg significantly affecting protein stability and structure .

• Autism Spectrum Disorder (ASD): Studies have found a higher frequency of mutations in the ABHD14A gene in individuals with ASD compared to the general population, with approximately 1% of individuals with ASD harboring mutations in this gene .

• Intellectual Disability (ID): ABHD14A mutations have been associated with impaired cognitive function and intellectual disability .

• Schizophrenia: Certain genetic variants in ABHD14A have been linked to an increased risk of developing schizophrenia .

• Alzheimer's Disease: Emerging research suggests ABHD14A may play a role in Alzheimer's disease progression through altered metabolism of N-acylethanolamine (NAE) .

What cellular pathways and molecular mechanisms might Abhd14a participate in?

While the specific pathways for Abhd14a are still being elucidated, several key functions have been proposed based on current research:

• Neurotransmitter regulation: ABHD14A appears to play a crucial role in regulating the levels of N-acylethanolamine (NAE), a neurotransmitter involved in modulating pain, appetite, and inflammation .

• Neuronal development: Biological function analyses and interconnection studies predict potential roles for ABHD14A in neuronal development pathways, which may explain its associations with neurodevelopmental disorders .

• Potential enzymatic roles: As a member of the abhydrolase domain-containing protein family, Abhd14a likely possesses hydrolase activity. The related ABHD14B functions as a lysine deacetylase, suggesting Abhd14a might have similar or complementary enzymatic functions, potentially in protein modification or signaling contexts .

• Transcriptional regulation: By analogy with ABHD14B, which interacts with histone acetyltransferase domains, Abhd14a may have roles in transcriptional regulation through similar protein-protein interactions or enzymatic activities .

How can structure-function analyses of Abhd14a inform potential therapeutic strategies?

Structure-function analyses of Abhd14a can provide valuable insights for therapeutic development through several approaches:

• Missense variant analysis: Investigations of variants like Leu230Arg have demonstrated significant effects on protein stability and structure, highlighting regions critical for proper function. These regions could serve as targets for small molecule stabilizers or function modulators .

• Catalytic site targeting: By identifying the catalytic residues and functional motifs, similar to those established for ABHD14B (catalytic triad, nucleophilic motif, acyltransferase motif), researchers can design specific inhibitors or activators that modulate Abhd14a activity .

• Allosteric regulation sites: Positions that may be subject to post-translational modifications, like S75 in ABHD14B, could represent allosteric regulatory sites in Abhd14a that might be targeted to modulate activity without directly affecting the catalytic site .

• Protein-protein interaction surfaces: Identifying interaction partners and the corresponding binding surfaces could lead to the development of molecules that disrupt or enhance specific protein-protein interactions, potentially modulating downstream signaling pathways.

How is Abhd14a evolutionarily conserved across species, and what does this reveal about its function?

Evolutionary analyses of ABHD14 family proteins have revealed important patterns of conservation:

Extensive phylogenetic analyses have mapped the presence of both ABHD14A and ABHD14B across evolutionary timescales. While ABHD14B has been identified in approximately 697 organisms spanning mammals, birds, ray-finned fishes (Actinopterygii), and reptiles, ABHD14A appears to be present in approximately 38% (263) of these organisms .

The phylogenetic relationships between ABHD14B sequences from different taxonomic groups show that avian ABHD14B sequences are most closely related to mammalian ones, while Actinopterygii and reptilian sequences form a separate cluster that is more closely related to mammalian ABHD14B than to avian ABHD14B .

These evolutionary patterns suggest that ABHD14A and ABHD14B likely diverged from a common ancestral gene, with ABHD14B potentially having more conserved functions across a broader range of organisms. The more restricted distribution of ABHD14A might indicate more specialized functions that evolved later or were lost in some lineages.

What experimental approaches are most suitable for cross-species functional comparisons of Abhd14a?

For researchers interested in comparative studies of Abhd14a across species, several methodological approaches are particularly valuable:

• Heterologous expression and biochemical characterization:

  • Expression of Abhd14a from different species in a common host system (e.g., HEK293T cells)

  • Comparative biochemical assays using standardized substrates and conditions

  • Analysis of kinetic parameters to identify functional differences

• Complementation studies:

  • Use of knockout or knockdown models in one species

  • Rescue experiments with Abhd14a from different species

  • Assessment of functional endpoints relevant to known Abhd14a activities

• Domain swapping experiments:

  • Creation of chimeric proteins with domains from Abhd14a of different species

  • Analysis of which domains confer species-specific functional properties

  • Identification of critical residues through targeted mutagenesis

• Conserved motif analysis:

  • Identification of species-specific variations in otherwise conserved motifs

  • Targeted mutagenesis to convert motifs from one species to another

  • Functional assessment of the impact of these changes

These approaches can provide insights into the functional evolution of Abhd14a and identify both conserved mechanisms and species-specific adaptations.

What are the common technical challenges in expressing and purifying functional Abhd14a, and how can they be addressed?

Researchers working with recombinant Abhd14a may encounter several technical challenges:

• Protein solubility issues:

  • Challenge: Hydrophobic regions may cause aggregation

  • Solution: Optimize expression conditions (temperature, induction time), use solubility-enhancing tags, or add mild detergents to purification buffers

• Maintaining enzymatic activity:

  • Challenge: Loss of activity during purification

  • Solution: Include stabilizing agents (glycerol, reducing agents), minimize freeze-thaw cycles, and optimize buffer conditions (25 mM Tris.HCl, pH 7.3, 100 mM glycine, 10% glycerol has proven effective)

• Heterogeneity in post-translational modifications:

  • Challenge: Variable modifications affecting activity

  • Solution: Select expression systems that closely mimic native modifications (mammalian cells like HEK293T for mammalian proteins) , or use site-directed mutagenesis to eliminate modification sites if they interfere with analyses

• Tag interference with function:

  • Challenge: Epitope tags affecting protein folding or activity

  • Solution: Compare N- and C-terminal tag positions, use cleavable tags, or validate activity with different tag configurations