Recombinant Macaca fascicularis Probable phospholipid-transporting ATPase VD (ATP10D)

What is ATP10D and what is its primary function in Macaca fascicularis?

ATP10D belongs to the P4-ATPase subfamily, functioning as a phospholipid flippase that maintains asymmetrical distribution of phospholipids across cell membrane bilayers. In Macaca fascicularis, ATP10D is predicted to enable ATPase-coupled intramembrane lipid transporter activity, specifically involved in phospholipid translocation processes. This protein plays a crucial role in membrane organization and lipid homeostasis .

How does the structure of ATP10D compare between primate species and humans?

The ATP10D protein in Macaca fascicularis shares significant structural homology with the human version. The recombinant form can be produced as a partial protein with high purity (>85% by SDS-PAGE). The protein contains characteristic domains of P-type ATPases necessary for phospholipid transport. Cross-species comparisons indicate conservation of key functional domains, suggesting evolutionary importance of this flippase activity .

What are the known sequence variants in ATP10D and their functional significance?

Variants such as c.410A>C (p.Lys137Thr) in human ATP10D cause missense changes that alter conserved nucleotides. This particular variant results in lysine being replaced by threonine at position 137. Computational analyses predict pathogenic outcomes for some variants, though many remain classified as having "uncertain significance." The functional effects of these variants on phospholipid transport activity require further investigation .

What are the optimal conditions for handling recombinant Macaca fascicularis ATP10D?

Storage Recommendations:

• Liquid form: 6 months shelf life at -20°C/-80°C

• Lyophilized form: 12 months shelf life at -20°C/-80°C

• Avoid repeated freezing and thawing

• Working aliquots can be stored at 4°C for up to one week

Reconstitution Protocol:

• Briefly centrifuge vial before opening

• Reconstitute in deionized sterile water to 0.1-1.0 mg/mL

• Add glycerol to 5-50% final concentration (50% recommended)

• Aliquot for long-term storage at -20°C/-80°C

What experimental systems are suitable for studying ATP10D function?

Current research employs several experimental systems for investigating ATP10D function:

• Primary cell cultures: Tenocytes isolated from tissues like masticatory muscle tendons have been used for gene expression studies under conditions such as mechanical stress

• Recombinant protein assays: E. coli-expressed recombinant proteins for biochemical characterization

• Transgenic animal models: Zebrafish and rodent models with ATP10D modifications

• Gene expression analyses: RNA-seq and microarray studies to analyze differential expression patterns

For mechanical stress studies specifically, cyclic sinusoidal equi-biaxial tensile strain at 1.0 Hz for 48 hours from low (0%) to high (10%) amplitude has been employed in primate tissue studies .

How can ATP10D activity be measured experimentally?

Experimental approaches to measure ATP10D activity include:

• Lipid flippase assays: Measuring translocation of fluorescently labeled phospholipids across membranes

• ATPase activity assays: Quantifying ATP hydrolysis rates using colorimetric or luminescent detection methods

• Gene expression quantification: RT-PCR or RNA-seq to measure transcript levels in response to various stimuli

• Protein expression analysis: Western blotting and immunohistochemistry to detect protein levels and localization patterns

These methodologies can be combined with ATP10D activators such as bezafibrate or phosphatidylserine substrates to evaluate functional responses .

What role does ATP10D play in disease susceptibility and progression?

ATP10D has been implicated in several disease processes:

• Cancer: ATP10D genetic variants have been associated with differential risk of developing tobacco-induced non-small cell lung cancer (NSCLC). Expression levels correlate with survival outcomes in early-stage NSCLC patients.

• Metabolic disorders: As a phospholipid transporter, ATP10D likely influences membrane composition and may affect signaling pathways involved in metabolic regulation.

Survival Data for ATP10D Expression in NSCLC:

This data suggests ATP10D may serve as a potential prognostic biomarker in certain cancers .

How do ATP10D genetic variations impact phospholipid homeostasis across species?

Cross-species studies suggest ATP10D function is conserved but with species-specific variations:

• Zebrafish: ATP10D is predicted to enable ATPase-coupled intramembrane lipid transporter activity and is located on chromosome 13

• Rat: ATP10D is predicted to function in glycosylceramide flippase activity

• Human: Variants such as p.Lys137Thr alter conserved residues with potentially pathogenic outcomes

• Macaca: Functions similarly to human ATP10D in phospholipid transport

These variations may reflect evolutionary adaptations to different membrane compositions or environmental pressures across species .

What compounds or environmental factors regulate ATP10D expression?

Several compounds have been shown to affect ATP10D expression in various species:

Upregulators:

• 1,2-dimethylhydrazine (increases expression)

• 17alpha-ethynylestradiol (increases expression)

• Aflatoxin B1 (increases expression)

• All-trans-retinoic acid (increases expression)

• 2-palmitoylglycerol (increases expression)

Downregulators:

• 2,3,7,8-tetrachlorodibenzodioxine (decreases expression)

• 2-hydroxypropanoic acid (lactic acid) (decreases expression)

Multiple interactions:

• (-)-epigallocatechin 3-gallate (multiple interactions)

What activators enhance ATP10D function and how do they work?

Two key activators have been identified:

• Bezafibrate: A fibrate drug that enhances ATP10D activity by modulating lipid metabolism, potentially increasing demand for lipid transport and stimulating the flippase activity of ATP10D.

• Phosphatidylserine: A phospholipid that upregulates lipid flippase activity of ATP10D by providing substrate availability, thereby enhancing its functional activity in maintaining lipid asymmetry in membranes .

How does ATP10D interact with other membrane proteins and lipid components?

ATP10D functions within a complex membrane environment where it:

• Interacts with specific phospholipid substrates, particularly aminophospholipids

• May coordinate with other membrane proteins involved in lipid transport and metabolism

• Responds to changes in membrane fluidity and composition

• Potentially forms protein complexes with regulatory partners

Understanding these interactions is critical for elucidating the full spectrum of ATP10D functions in cellular homeostasis and disease processes .

What technologies are emerging for studying ATP10D structure-function relationships?

Emerging technologies for ATP10D research include:

• Cryo-electron microscopy: For high-resolution structural determination of ATP10D in different conformational states

• Advanced lipid imaging techniques: To visualize phospholipid flipping in real-time

• CRISPR-Cas9 genome editing: For creating precise mutations to study structure-function relationships

• Single-molecule studies: To analyze ATP10D dynamics during its catalytic cycle

• Computational modeling: To predict effects of mutations and identify potential binding sites for activators

These approaches will help address current knowledge gaps regarding ATP10D mechanism of action .

How might ATP10D be targeted therapeutically in disease conditions?

Based on current understanding, potential therapeutic approaches involving ATP10D include:

• Activation strategies: Using compounds like bezafibrate to enhance ATP10D activity in conditions where it may be deficient

• Expression modulation: Targeting transcriptional regulators to increase ATP10D expression in specific tissues

• Mutation correction: Developing approaches to address dysfunctional ATP10D variants

• Cancer biomarkers: Utilizing ATP10D expression patterns as prognostic or predictive biomarkers in cancer treatment decisions