Recombinant Arabidopsis thaliana Putative ALA-interacting subunit 2 (ALIS2)
Description
Introduction to ALIS2
ALIS2 belongs to the Cdc50-like protein family that serves as β-subunits for P4-ATPases in Arabidopsis thaliana. These P4-ATPases, also known as phospholipid flippases, are believed to catalyze the flipping of phospholipids across cellular membranes, contributing significantly to vesicle biogenesis in both secretory and endocytic pathways. The formation of heteromeric complexes between P4-ATPases and Cdc50-like proteins such as ALIS2 is integral to this process, with these β-subunits playing a crucial role in the P4-ATPase transport machinery . Arabidopsis thaliana, with its relatively small genome size of approximately 135 Mb, serves as an excellent model organism for studying these plant-specific protein interactions . The production of recombinant ALIS2 has enabled researchers to investigate its structural properties and functional characteristics more thoroughly, providing insights into membrane dynamics in plant cells.
Historical Context and Discovery
The identification of ALIS2 emerged from broader studies of membrane transport mechanisms in plants. Research into phospholipid flippases revealed the importance of P4-ATPases in maintaining membrane asymmetry and facilitating vesicular transport. The discovery that these ATPases require binding partners for proper functioning led to the identification of several ALA-interacting subunits, including ALIS2. While the search results don't provide the exact discovery timeline, this protein has become recognized as a critical component in understanding plant membrane biology.
Classification and Nomenclature
ALIS2 is classified among the Cdc50-like proteins that function as β-subunits for P4-ATPases. The nomenclature "ALA-interacting subunit 2" directly reflects its functional relationship with ALA (Aminophospholipid ATPase) proteins in Arabidopsis thaliana. This naming convention emphasizes the protein's role as an interacting partner rather than a standalone functional unit. The "Putative" designation in its full name indicates that while substantial evidence supports its proposed function, some aspects of its activity may still require additional experimental validation.
Protein Structure
The recombinant production of ALIS2 has provided opportunities to study its structural characteristics more precisely. Like other Cdc50-like proteins, ALIS2 likely features multiple membrane-spanning regions that integrate it into cellular membranes. These transmembrane domains play a crucial role in positioning the protein to interact effectively with its ALA partners. The extracellular portions of the protein may also contribute to recognition and binding of specific phospholipid substrates, though detailed structural analyses would be needed to confirm this hypothesis.
Molecular Properties
As a β-subunit protein, ALIS2 likely exhibits specific molecular properties that facilitate its interaction with ALA proteins. These properties would include appropriate surface charges and hydrophobic regions that enable stable binding to the catalytic α-subunit. The recombinant production of ALIS2 allows for detailed biochemical characterization, including determination of molecular weight, isoelectric point, and binding affinities for various ALA proteins.
Role in Phospholipid Transport
The primary function of ALIS2 appears to be supporting P4-ATPase activity in phospholipid translocation. P4-ATPases are responsible for flipping specific phospholipids from the outer to the inner leaflet of cellular membranes, a process critical for establishing and maintaining membrane asymmetry. ALIS2, as a β-subunit, likely facilitates this activity through direct interaction with ALA proteins, though the exact mechanism by which it enhances flippase activity remains an area of active investigation.
Involvement in Cellular Processes
Beyond its direct role in phospholipid transport, ALIS2 likely contributes to various cellular processes that depend on membrane dynamics. By supporting phospholipid flipping, ALIS2 indirectly influences vesicle formation, membrane curvature, and potentially signal transduction pathways that rely on specific membrane compositions. Similar to the AP2 complex that plays an essential role in clathrin-mediated endocytosis in Arabidopsis , ALIS2-containing complexes may participate in specific membrane trafficking pathways, though this would require further experimental validation.
Interaction with ALA Proteins and P4-ATPases
The name "ALA-interacting subunit 2" directly reflects ALIS2's primary function: interaction with ALA proteins (P4-ATPases) in Arabidopsis. This interaction forms the basis for functional phospholipid flippase complexes. From the search results, we can infer that P4-ATPases form heteromeric complexes with Cdc50-like proteins such as ALIS2, and these complexes are necessary for phospholipid translocation across membranes .
Binding Mechanisms
The binding between ALIS2 and ALA proteins likely involves specific recognition domains on both proteins. These interactions must be sufficiently stable to maintain functional complexes while potentially allowing for regulation through association and dissociation. Research on P4-ATPases has demonstrated that cellular targeting and lipid specificity require the α-subunit (ALA protein) but may be independent of the β-subunit (such as ALIS2) . This suggests that while ALIS2 is necessary for proper functioning of the complex, the specificity determinants reside primarily with the ALA protein.
Functional Significance of Interaction
The formation of complexes between ALIS2 and ALA proteins has significant functional implications. Research indicates that while the ALA α-subunit determines lipid specificity and cellular targeting, the interaction with β-subunits like ALIS2 may be essential for proper trafficking, stability, or activation of the complex . The production of recombinant ALIS2 has facilitated investigations into these interactions, allowing researchers to study complex formation in controlled experimental settings.
Methods of Recombinant ALIS2 Production
The production of recombinant ALIS2 involves expressing the protein in laboratory systems to obtain sufficient quantities for experimental analysis. While the search results don't provide specific methods for ALIS2 production, the recombinant expression of membrane proteins typically employs established molecular biology techniques.
Expression Systems
Recombinant ALIS2 production likely utilizes expression systems suitable for membrane proteins. These could include bacterial systems like Escherichia coli, yeast systems such as Pichia pastoris, insect cell systems using baculovirus, or plant-based expression systems. Each system offers different advantages in terms of protein folding, post-translational modifications, and yield. For a plant membrane protein like ALIS2, systems that provide appropriate membrane insertion machinery would be particularly valuable.
Purification and Characterization
After expression, recombinant ALIS2 would typically undergo purification using techniques suited to membrane proteins. These might include detergent solubilization followed by affinity chromatography, particularly if the recombinant protein includes affinity tags. Subsequent characterization might involve mass spectrometry, circular dichroism spectroscopy, or structural analyses through crystallography or cryo-electron microscopy. These approaches would provide insights into the protein's molecular properties and structural features.
Applications and Research Significance
The production of recombinant ALIS2 has significant implications for research into plant membrane biology and phospholipid transport mechanisms. By making this protein available in purified form, researchers can conduct detailed studies of its structure, interactions, and function.
Experimental Applications
Recombinant ALIS2 serves numerous experimental purposes, including structural studies, interaction analyses, and functional assays. Researchers can use purified ALIS2 to investigate its binding to different ALA proteins, assess how these interactions influence phospholipid flipping activity, and explore potential regulatory mechanisms. Additionally, recombinant ALIS2 can serve as an antigen for antibody production, facilitating immunological detection of the native protein in plant tissues.
Contributions to Understanding Plant Physiology
Research involving recombinant ALIS2 contributes to our broader understanding of plant physiology, particularly membrane dynamics and vesicular transport. By elucidating the role of ALIS2 in phospholipid flipping, researchers gain insights into fundamental cellular processes that influence plant development, stress responses, and environmental adaptation. This knowledge may eventually inform agricultural applications or biotechnological innovations.
Current Research and Future Directions
Research on ALIS2 and related proteins continues to advance our understanding of membrane biology in plants. Current investigations likely focus on detailed characterization of ALIS2's structure, its specific interactions with different ALA proteins, and the functional consequences of these interactions.
Recent Findings
While the search results don't provide recent findings specifically about ALIS2, research on P4-ATPases and their β-subunits has revealed important insights into their function. Studies have demonstrated that the α-subunit (ALA protein) determines lipid specificity and cellular targeting, while the role of β-subunits like ALIS2 may be more complex than initially thought . These findings suggest that ALIS2 may serve functions beyond simply stabilizing or activating its ALA partners.
Future Research Directions
Future research on ALIS2 may explore several promising directions. These could include detailed structural analyses to understand precisely how ALIS2 interacts with ALA proteins, investigations into potential regulatory mechanisms that control complex formation or activity, and studies of how ALIS2-containing complexes participate in specific cellular processes. Additionally, comparative analyses of different ALIS proteins might reveal specialized functions or subcellular localizations that contribute to the diverse roles of phospholipid flippases in plant cells.
Product Specs
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Note: Our proteins are shipped with standard blue ice packs. If you require dry ice shipping, please communicate with us in advance as additional fees will apply.
Generally, liquid forms have a shelf life of 6 months at -20°C/-80°C. Lyophilized forms have a shelf life of 12 months at -20°C/-80°C.
Target Background
Q&A
What is the function of ALIS2 in Arabidopsis thaliana?
ALIS2 functions as a beta-subunit that interacts with Aminophospholipid ATPases (ALAs), particularly facilitating the proper localization and functionality of ALA flippases. Similar to other ALIS proteins (ALIS1, ALIS3, ALIS5), ALIS2 likely enables ALAs to exit the endoplasmic reticulum (ER) and reach their final cellular destination . Without ALIS partners, ALA proteins often remain trapped in the ER, rendering them non-functional. The interaction between ALIS2 and various ALA proteins (like ALA1 and ALA2) is critical for processes including antiviral immunity and membrane phospholipid asymmetry maintenance .
How does ALIS2 differ from other ALIS family members?
ALIS2 belongs to the same family as ALIS1, ALIS3, and ALIS5, sharing structural similarities but potentially having distinct expression patterns and ALA partner preferences. While specific ALIS2 information is limited in current research, studies of other ALIS members indicate they all facilitate ALA transport from the ER to their final destinations, but may differ in tissue-specific expression, ALA partner preferences, and regulatory mechanisms . The functional redundancy between ALIS family members is evidenced by observations that ALIS1, ALIS3, and ALIS5 can all promote proper localization of ALA2 and ALA3, suggesting potentially similar capabilities for ALIS2 .
What experimental techniques are used to study ALIS2-ALA interactions?
Several experimental approaches are employed to study ALIS2-ALA interactions:
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Yeast complementation assays: Using yeast strains deficient in flippase activity to test whether co-expression of recombinant ALA and ALIS proteins can restore function .
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Fluorescent protein fusion localization: Tagging ALIS2 and ALAs with fluorescent proteins (like GFP) to visualize their subcellular localization through confocal microscopy .
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Co-immunoprecipitation: Evaluating physical interactions between ALIS2 and ALA proteins.
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Mutant phenotype analysis: Comparing wild-type, single, double, and triple mutants to assess functional relationships, as demonstrated with ALA1/ALA2 studies .
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Lipid translocation assays: Measuring the flipping of fluorescently-labeled phospholipids across membranes to assess functional activity of ALA-ALIS complexes.
How should I design experiments to study ALIS2 function in Arabidopsis?
When designing experiments to study ALIS2 function, implement a systematic approach following these methodological principles:
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Define your variables clearly:
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Generate appropriate genetic materials:
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Employ a between-subjects experimental design:
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Include appropriate controls:
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Validate results with complementary approaches:
What are the best methods for producing recombinant ALIS2 protein?
To produce high-quality recombinant ALIS2 protein for biochemical and structural studies:
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Expression system selection:
Expression System Advantages Disadvantages Best Use Case E. coli Fast growth, high yield May not provide proper folding or post-translational modifications Initial protein characterization Yeast Eukaryotic processing, moderate yield Longer growth time than bacteria Functional studies requiring proper folding Insect cells High-quality eukaryotic processing More complex and expensive Structural biology applications Plant expression Native modifications Lower yield, time-consuming Plant-specific interaction studies -
Fusion tags optimization:
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Solubilization and purification protocol:
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Quality control measures:
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SDS-PAGE and western blot to confirm purity and identity
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Circular dichroism to assess secondary structure integrity
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Dynamic light scattering to evaluate homogeneity
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How can I verify ALIS2-ALA interactions in planta?
To verify ALIS2-ALA interactions in Arabidopsis:
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Bimolecular Fluorescence Complementation (BiFC):
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Co-immunoprecipitation from plant tissues:
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Express epitope-tagged versions (HA, FLAG, Myc) of ALIS2 and ALA proteins
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Immunoprecipitate protein complexes using tag-specific antibodies
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Detect interaction partners via western blotting
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Subcellular co-localization studies:
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Genetic interaction analysis:
How does ALIS2 contribute to ALA-mediated antiviral immunity?
ALIS2 likely contributes to antiviral immunity through facilitating proper trafficking and function of ALA flippases. While specific ALIS2 data is limited, research on related proteins provides insights into potential mechanisms:
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Membrane composition regulation:
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RNAi pathway support:
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Experimental evidence from ALA studies:
To investigate ALIS2's specific role in this process, researchers should generate alis2 single and alis2 ala1/2 double mutants and assess their response to viral challenge compared to established ala mutants.
What is the structural basis for ALIS2 specificity toward different ALA partners?
The structural determinants of ALIS2 specificity toward different ALA partners remain largely undefined, but likely involve:
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Protein domain architecture:
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Experimental approaches to determine specificity:
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Site-directed mutagenesis of conserved vs. divergent residues
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Domain swapping between different ALIS proteins
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Hydrogen-deuterium exchange mass spectrometry to map interaction interfaces
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Cryo-electron microscopy of ALIS2-ALA complexes
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Co-evolutionary analysis:
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Comparing evolutionary rates between ALIS and ALA family members
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Identifying co-evolved residues that might form interaction networks
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Using this information to predict preferential binding partners
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How do environmental stresses modulate ALIS2-ALA interactions?
Environmental stresses likely influence ALIS2-ALA interactions through:
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Transcriptional regulation:
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Post-translational modifications:
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Phosphorylation, ubiquitination, or other modifications might regulate ALIS2-ALA binding affinity
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Stress-activated kinases could modulate these interactions through direct protein modification
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Membrane environment changes:
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Stress-induced alterations in membrane fluidity and composition
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Temperature, oxidative stress, or pathogen challenge may trigger reorganization of membrane domains where ALIS2-ALA complexes function
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Experimental approaches:
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Transcriptome analysis under various stress conditions
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Co-immunoprecipitation under stress vs. control conditions
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FRET-based interaction assays in living plants subjected to stress treatments
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How can I overcome expression difficulties when working with recombinant ALIS2?
Membrane proteins like ALIS2 present numerous expression challenges. Consider these solutions:
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Optimizing expression conditions:
Challenge Solution Implementation Poor expression Lower induction temperature Reduce to 16-20°C during induction phase Protein aggregation Add solubilizing agents Include 5-10% glycerol and mild detergents Toxicity to host Use tightly regulated promoters Switch to pET vectors with T7lac promoter Poor membrane integration Add signal sequences Fuse with established membrane protein leader sequences Proteolytic degradation Include protease inhibitors Add PMSF, EDTA, and complete protease inhibitor cocktail -
Expression construct modifications:
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Alternative expression systems:
What controls should be included when analyzing phenotypes of alis2 mutants?
When analyzing alis2 mutant phenotypes, include these essential controls:
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Genetic controls:
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Wild-type plants of identical ecotype background
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Multiple independent alis2 mutant alleles to confirm phenotype specificity
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Complementation lines expressing ALIS2 under native promoter
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Other alis single mutants (alis1, alis3, alis5) to assess family member-specific effects
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Technical controls:
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Developmental controls:
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Molecular validation:
What emerging technologies could advance our understanding of ALIS2 function?
Several cutting-edge technologies could significantly enhance ALIS2 research:
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CRISPR-Cas9 genome editing:
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Advanced imaging techniques:
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Super-resolution microscopy (STORM, PALM) to visualize nanoscale organization of ALIS2-ALA complexes
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Live-cell single-molecule tracking to monitor dynamics of ALIS2-ALA interactions
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Correlative light and electron microscopy to link protein localization with membrane ultrastructure
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Proteomics approaches:
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Proximity labeling (BioID, APEX) to identify novel ALIS2 interactors in native plant tissues
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Quantitative interaction proteomics under different environmental conditions
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Phosphoproteomics to map regulatory post-translational modifications
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Structural biology methods:
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Cryo-electron microscopy of ALIS2-ALA complexes
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Hydrogen-deuterium exchange mass spectrometry to map dynamic interactions
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AlphaFold2 or RoseTTAFold structure prediction validated by experimental approaches
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How might ALIS2 function in regulating plant responses to climate change stressors?
ALIS2 may play important roles in plant adaptation to climate change stressors:
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Temperature stress responses:
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Drought and salinity tolerance:
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Membrane phospholipid composition affects water permeability and ion transport
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ALIS2-dependent ALA localization could be crucial for maintaining membrane integrity during water stress
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Phospholipid asymmetry may influence signaling pathways related to ABA responses
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Pathogen resistance under changing climate:
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Research approaches:
