Recombinant Danio rerio Transmembrane protein 201 (tmem201)

What is Recombinant Danio rerio Transmembrane Protein 201?

Recombinant Danio rerio Transmembrane protein 201 (tmem201) is an inner nuclear membrane protein that has been identified as crucial for endothelial cell migration and angiogenesis. The protein can be produced recombinantly in yeast systems with a purity of >85% as determined by SDS-PAGE. It is associated with UniProt accession number A4IG66 and is available in both partial and full-length forms for research applications. The protein is part of the nuclear envelope architecture, specifically localized to the inner nuclear membrane, where it participates in critical cellular functions related to vascular development .

What are the structural characteristics of tmem201 in zebrafish?

The tmem201 protein in Danio rerio is characterized by its transmembrane domains that anchor it to the inner nuclear membrane. Unlike some other membrane proteins, tmem201 features specific domains that facilitate interactions with the linker of nucleoskeleton and cytoskeleton (LINC) complex. The N-terminal domain of tmem201 has been identified as particularly important for these interactions and is required for its functions in regulating endothelial cell migration and angiogenesis. When working with recombinant versions, researchers should pay careful attention to whether full-length or partial constructs are being used, as this may affect experimental outcomes and interpretation of results .

How should recombinant tmem201 be stored and reconstituted for optimal activity?

For optimal results when working with recombinant tmem201, follow this reconstitution protocol: Briefly centrifuge the vial prior to opening to bring the contents to the bottom. Reconstitute the protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL. For long-term storage, add glycerol to a final concentration of 5-50% (with 50% being standard practice) and aliquot for storage at -20°C/-80°C. The shelf life of liquid preparations is generally 6 months at -20°C/-80°C, while lyophilized forms can be stored for up to 12 months at the same temperatures. Importantly, repeated freeze-thaw cycles should be avoided. For short-term use, working aliquots can be stored at 4°C for up to one week without significant loss of activity .

How does tmem201 influence endothelial cell migration?

Tmem201 regulates endothelial cell migration through its interactions with the linker of nucleoskeleton and cytoskeleton (LINC) complex. Research has shown that the N-terminal domain of tmem201 is required for these interactions and subsequent functionality. When tmem201 expression is depleted via short hairpin RNA-mediated interference, human umbilical vein endothelial cells (HUVECs) demonstrate impaired migration ability. Additionally, tmem201 deficiency has been shown to affect endothelial cell polarity, with the Golgi apparatus reorientation ratio reduced to approximately 24% in tmem201-deficient HUVECs compared to 45.6% in control cells. This indicates that tmem201 is crucial for establishing endothelial polarity during directional migration. Interestingly, this function does not appear to directly affect VEGF signaling pathways, suggesting alternative mechanisms are involved in tmem201-mediated regulation of endothelial cell migration .

What are the key considerations when designing knockdown/knockout experiments for tmem201?

When designing knockdown or knockout experiments for tmem201, researchers should consider several critical factors. First, select appropriate model systems—both in vitro cell models (such as HUVECs) and in vivo models (zebrafish or mice) have proven effective for studying tmem201 function. For knockdown approaches, short hairpin RNA-mediated interference has been successfully employed. For knockout models, CRISPR/Cas9 technology has been validated for generating tmem201-/- mice and zebrafish. It's essential to include proper controls, including wild-type comparisons and rescue experiments to confirm phenotype specificity. When assessing angiogenic phenotypes, researchers should evaluate multiple parameters including tube formation, sprouting capacity, migration ability, and in vivo vascular development (such as retinal vessel development in mice or intersegmental vessel formation in zebrafish). Finally, verification of knockout/knockdown efficiency through protein expression analysis is crucial for result interpretation .

What assays are most effective for evaluating tmem201 function in angiogenesis studies?

Based on published research, the following assays have proven most effective for evaluating tmem201 function in angiogenesis studies:

These assays provide complementary information about different aspects of tmem201's role in angiogenesis, from cellular migration to complete vascular network formation in living organisms .

How does the N-terminal domain of tmem201 interact with the LINC complex to regulate endothelial cell function?

The N-terminal domain of tmem201 serves as a critical interaction interface with the linker of nucleoskeleton and cytoskeleton (LINC) complex. This interaction forms the molecular basis for tmem201's role in regulating nuclear positioning, which subsequently affects cell migration and polarity. Research has demonstrated that truncation or deletion of the N-terminal domain renders tmem201 unable to rescue angiogenic defects in knockout models, underscoring its functional importance. Specifically, in zebrafish rescue experiments, while full-length tmem201 reduced the proportion of embryos with defective intersegmental vessels from 44.4% to 27.7%, the N-terminus deleted version (tmem201△N-terminus) failed to provide rescue (43.8% defective vessels). Mechanistically, this suggests that the N-terminal domain mediates force transmission between the cytoskeleton and nucleus, enabling appropriate nuclear positioning during cell migration. Future research should focus on identifying the specific amino acid residues within the N-terminal domain that mediate these protein-protein interactions and how these interactions are regulated in different cellular contexts .

What are the comparative functions of tmem201 across different species and what does this reveal about evolutionary conservation?

While research on tmem201 is still developing, available evidence suggests significant functional conservation across species. In humans, TMEM201 (also known as Samp1) has been identified as a positive modulator of breast cancer cell invasion and migration. Similarly, in zebrafish, tmem201 regulates endothelial cell migration and vascular development. In mice, Tmem201 knockout results in defective retinal vessel development and impaired aortic ring sprouting. This functional conservation suggests that tmem201 emerged early in vertebrate evolution as an important regulator of cell migration and vascular morphogenesis.

The degree of protein sequence homology between species would provide additional insight into evolutionary conservation, but detailed sequence comparison data is not currently available in the search results. Future research should focus on comparing the functional domains (particularly the N-terminal domain) across species to identify conserved motifs that mediate protein-protein interactions with the LINC complex. Additionally, investigating tmem201 function in invertebrate models could further illuminate the evolutionary history of this protein family and its role in basic cellular processes versus specialized vascular functions .

What are the optimal protein expression systems for producing functional recombinant tmem201?

Based on available research data, both yeast and E. coli expression systems have been successfully employed to produce recombinant tmem201 proteins. For partial tmem201 constructs, yeast-based expression systems have yielded proteins with >85% purity as determined by SDS-PAGE. For transmembrane proteins in the same family, E. coli expression systems have been effective for producing full-length constructs with N-terminal His tags. When selecting an expression system, researchers should consider:

• Protein size and complexity: Full-length tmem201 may benefit from eukaryotic expression systems like yeast that can handle complex folding requirements.

• Post-translational modifications: If native modifications are important for function, yeast offers advantages over bacterial systems.

• Purification strategy: His-tagging is commonly employed for easier purification via affinity chromatography.

• Yield requirements: E. coli systems typically offer higher yields but may sacrifice proper folding of complex proteins.

• Downstream applications: The choice between full-length and partial constructs should be guided by the specific research questions being addressed.

The reconstitution protocol is equally important, with recommended procedures including centrifugation prior to opening, reconstitution in deionized sterile water to 0.1-1.0 mg/mL, and addition of glycerol (5-50%) for long-term storage at -20°C/-80°C .

What techniques are most reliable for verifying tmem201 localization and interactions in cellular contexts?

For researchers investigating tmem201 localization and interactions, multiple complementary techniques should be employed:

For tmem201 specifically, confirming inner nuclear membrane localization is essential, as is verifying interactions with the LINC complex components. The choice between these techniques should be guided by the specific research question, available resources, and required resolution. Multiple approaches used in combination provide the most reliable results .

What are common challenges in working with recombinant tmem201 and how can they be addressed?

Researchers working with recombinant tmem201 may encounter several challenges that can impact experimental outcomes. Here are common issues and their solutions:

Additionally, when performing functional assays with tmem201, ensure proper controls are included and verification of protein expression or knockdown efficiency is conducted. For cellular localization studies, fixation methods should be optimized to preserve nuclear envelope structure .

How can researchers validate the specificity of phenotypes observed in tmem201 knockdown or knockout studies?

To ensure that phenotypes observed in tmem201 knockdown or knockout studies are specific and not due to off-target effects or compensatory mechanisms, researchers should implement several validation approaches:

These approaches collectively enhance confidence in the specificity of observed phenotypes and provide deeper insight into tmem201 function in various biological contexts .

What are the most promising research avenues for understanding tmem201 function in disease models?

Given the established role of tmem201 in endothelial cell migration and angiogenesis, several promising research avenues emerge for exploring its function in disease models:

• Cancer angiogenesis: Since tmem201 regulates endothelial cell migration, investigating its role in tumor angiogenesis could reveal new therapeutic targets. Previous research has already shown that TMEM201 modulates breast cancer cell invasion and migration, suggesting potential implications for tumor progression.

• Cardiovascular disorders: Given tmem201's role in vascular development, studying its involvement in cardiovascular diseases characterized by abnormal angiogenesis, such as atherosclerosis or restenosis, could provide new insights into disease mechanisms.

• Retinopathies: The observed defects in retinal vessel development in Tmem201-knockout mice suggest potential involvement in retinopathies like diabetic retinopathy or retinopathy of prematurity.

• Developmental disorders: Since tmem201 knockout impairs zebrafish intersegmental vessel development, investigating its role in human developmental vascular disorders could be fruitful.

• Wound healing and tissue regeneration: The role of tmem201 in endothelial cell migration suggests potential involvement in wound healing processes, which rely heavily on angiogenesis.

• Interaction with mechanotransduction pathways: Exploring how tmem201, through its interactions with the LINC complex, responds to mechanical forces and influences endothelial cell behavior in different flow conditions.

• Drug discovery: Screening for small molecules that modulate tmem201 function or its interactions with the LINC complex could yield new therapeutic approaches for angiogenesis-related disorders .

What technological advances would enhance our ability to study tmem201 dynamics and function?

Several technological advances would significantly enhance our understanding of tmem201 dynamics and function:

• CRISPR-based visualization systems: Adaptation of CRISPR-based technologies (such as CRISPR-Sirius) for live visualization of tmem201 localization and dynamics would allow real-time tracking of the protein during cell migration and angiogenesis.

• Advanced protein interaction mapping: Application of techniques like BioID, APEX2 proximity labeling, or cross-linking mass spectrometry would provide comprehensive maps of tmem201 interaction networks in different cellular contexts.

• Cryo-electron microscopy: Structural determination of tmem201 alone and in complex with interaction partners would provide molecular insights into its function and could guide structure-based drug design efforts.

• Single-cell multi-omics: Integration of single-cell transcriptomics, proteomics, and epigenomics would reveal how tmem201 functions in heterogeneous cell populations within developing vasculature.

• Advanced in vitro vascular models: Development of microfluidic-based vascular models incorporating flow conditions would enable more physiologically relevant studies of tmem201 function in endothelial cells.

• In vivo imaging technologies: Enhanced resolution in live imaging of developing zebrafish or mouse embryos would allow detailed tracking of vessel formation in tmem201 mutant models.

• Computational modeling: Integration of experimental data into mathematical models of cell migration and angiogenesis would help predict how tmem201 perturbations affect complex biological processes.

• Tissue-specific and inducible knockout systems: More refined genetic tools would allow temporal and spatial control of tmem201 expression, helping distinguish between its developmental and homeostatic functions.

These technological advances would collectively provide unprecedented insights into the molecular mechanisms by which tmem201 regulates endothelial cell function and vascular development .