Recombinant Pongo abelii Transmembrane protein 183 (TMEM183)

What is the molecular structure of Pongo abelii TMEM183?

Pongo abelii TMEM183 is a transmembrane protein consisting of 387 amino acids with the UniProt accession number Q5R8D5. The complete amino acid sequence is: MARGPGPLGRPRPDTVAMPKRGKRLKFRAHDACSGRVTVADYANSDPAVVRSGRVKKAVANAVQQEVKSLCGLEASQVPTEEALSGAGEPCDIIDSSDEMEAQEESIHERTVSRKKKSKRHKEELDGAGEEYPMDIWLLLASYIRPEDIVNFSLICKNAWTVTCTAAFWTRLYRRHYTLDASLPLRLRPESMEKLRCLRACVIRSLYHMYEPFAARISKNPAIPESTPSTLKNSKCLLF WCRKIVGNRQEPMWEFNFKFKKQSPRLKSKCTGGLQPPVQYEDVHTNPDQDCCLLQVTTLNFIFIPIVMGMIFTLFTINVSTDMRHHRVRLVFQDSPVHGGRKPRSEQGVQVILDPVHSVRLFDWWHPQYPFSLRALLLPIPWGQPRV .

The protein has characteristic transmembrane domains that anchor it to cellular membranes, with intervening intracellular and extracellular regions that likely participate in signaling or protein-protein interactions. Structural analysis using computational approaches such as hydropathy plots, domain prediction algorithms, and comparative modeling with similar transmembrane proteins would be valuable first steps in characterizing this protein.

How is recombinant Pongo abelii TMEM183 typically produced and purified?

Recombinant Pongo abelii TMEM183 is commonly produced through heterologous expression systems using the full-length protein coding sequence (position 1-387). The protein can be tagged, such as with an HA-tag or other affinity tags, to facilitate purification and detection . For membrane proteins like TMEM183, expression systems such as HEK293 or insect cells are often preferred over bacterial systems due to their ability to properly fold and post-translationally modify complex transmembrane proteins.

The purification typically involves cell lysis with detergents to solubilize the membrane protein, followed by affinity chromatography targeting the fusion tag. For storage, the purified protein is maintained in a Tris-based buffer with 50% glycerol to stabilize the protein structure . Researchers should avoid repeated freeze-thaw cycles and prepare small working aliquots stored at 4°C for short-term use, while keeping the stock at -20°C or -80°C for extended storage.

What experimental applications is recombinant TMEM183 suitable for?

Recombinant Pongo abelii TMEM183 is suitable for a variety of experimental applications, including:

• Immunological assays - serving as an antigen for antibody production or as a standard in ELISA assays

• Protein-protein interaction studies - identifying binding partners through co-immunoprecipitation or pull-down assays

• Functional characterization - examining its role in cellular processes through overexpression or knockdown studies

• Comparative analyses - investigating evolutionary conservation across primate species

• Structural studies - determining three-dimensional protein structure through crystallography or cryo-EM

The commercially available recombinant protein is typically provided at a concentration of 50 μg, which is sufficient for multiple experimental replicates in most assay types . When designing experiments, researchers should consider the native cellular localization of TMEM183 and utilize appropriate membrane-containing systems or detergent conditions for optimal results.

What are the known cellular functions of TMEM183 and its homologs across species?

While specific functions of Pongo abelii TMEM183 remain largely uncharacterized, insights may be drawn from studies of related TMEM proteins. For instance, TMEM182, another transmembrane protein family member, has been shown to inhibit myocardial differentiation of human induced pluripotent stem cells (hiPSCs), specifically affecting early stages of cardiac development . TMEM182 appears to function through inactivation of GSK-3β via phosphorylation of AKT, subsequently promoting nuclear translocation of β-catenin .

Another family member, TMEM18, has been extensively studied in relation to obesity and metabolic regulation, showing associations with BMI and waist circumference. TMEM18 expression in the prefrontal cortex demonstrates strong positive correlation with body weight (r=0.5694, P=0.0003), suggesting involvement in higher neural functions related to feeding behavior .

For TMEM183 specifically, limited data indicates potential involvement in bone development and response to gravitational changes, as it was identified in a differential expression analysis examining effects of microgravity and hypergravity, showing a modest downregulation (-0.215 fold change, p=3.25E-02) . Researchers investigating TMEM183 should design experiments that examine its potential roles in these pathways, perhaps beginning with expression profiling across tissues and developmental stages.

How might TMEM183 function differ between humans and non-human primates?

Investigating functional differences of TMEM183 between humans and non-human primates represents an important evolutionary question. Researchers should consider comparative genomics approaches, beginning with sequence alignment and phylogenetic analysis of TMEM183 across primate species to identify conserved domains and species-specific variations.

Expression pattern analyses across homologous tissues in different primate species would provide valuable insights into potential functional divergence. For example, single-cell RNA sequencing of matching tissue types from human and orangutan samples could reveal species-specific expression patterns. Additionally, in vitro functional assays comparing the human and Pongo abelii TMEM183 proteins in identical cellular contexts would help determine whether any sequence differences translate to functional differences.

Since TMEM183 may be involved in bone development based on its differential expression in microgravity studies , and considering that skeletal adaptations differ significantly between arboreal primates like orangutans and terrestrial bipedal humans, researchers might specifically investigate its role in osteogenic processes across species. This could involve osteoblast differentiation assays comparing the effects of human versus Pongo abelii TMEM183 expression.

What protein interaction networks might TMEM183 participate in?

To elucidate the protein interaction networks of TMEM183, researchers should employ a multi-faceted approach combining both computational prediction and experimental validation. Initial bioinformatic analyses might use tools like STRING, BioGRID, and InterPro to predict potential interaction partners based on sequence homology, co-expression data, and domain structure.

Experimentally, techniques such as proximity-dependent biotin identification (BioID), co-immunoprecipitation followed by mass spectrometry, or yeast two-hybrid screening could identify direct and indirect interaction partners. Based on the limited information available about TMEM family proteins, possible interaction networks might involve:

• Components of WNT/β-catenin signaling pathway, given the relationship between TMEM182 and β-catenin nuclear translocation

• Factors involved in bone metabolism, considering TMEM183's differential expression in microgravity conditions

• Membrane trafficking machinery, common for many transmembrane proteins

When investigating these interactions, researchers should be mindful that membrane proteins often require specialized approaches to maintain their native conformation and interaction capabilities. Detergent selection, membrane mimetics, or in-cell approaches may be necessary for accurate results.

What are the optimal expression systems for studying TMEM183 function?

When selecting expression systems for TMEM183 functional studies, researchers should consider several factors specific to transmembrane proteins. Mammalian expression systems like HEK293, CHO, or COS-7 cells generally provide the most native-like environment for proper folding and post-translational modifications of primate transmembrane proteins.

For studying protein-protein interactions or cellular localization, researchers might employ:

• Inducible expression systems (e.g., tetracycline-regulated) to control expression levels and timing

• Fusion with fluorescent proteins (e.g., GFP, mCherry) for live-cell imaging

• Split reporter systems (e.g., split-GFP or split-luciferase) for studying protein-protein interactions in live cells

Based on approaches used for related TMEM proteins, researchers have successfully employed DOX-inducible expression systems when studying TMEM182's effects on cellular differentiation . This approach allows precise temporal control of expression, which is particularly valuable when studying proteins that may have stage-specific developmental effects.

What approaches are recommended for investigating TMEM183 in cellular models?

Investigating TMEM183 in cellular models requires systematic approaches to determine localization, expression patterns, and functional consequences of manipulation. Researchers should consider the following methodological pipeline:

• Subcellular localization determination:

  • Immunofluorescence with specific antibodies or tagged recombinant proteins

  • Subcellular fractionation followed by Western blotting

  • Live-cell imaging with fluorescently tagged TMEM183

• Expression manipulation strategies:

  • CRISPR/Cas9-mediated knockout or knockin

  • RNA interference (siRNA or shRNA) for transient or stable knockdown

  • Overexpression using constitutive or inducible promoters

• Functional readouts:

  • Transcriptomic profiling to identify downstream effects

  • Phenotypic assays targeting pathways suggested by preliminary data (e.g., cell differentiation, response to mechanical stress)

  • Calcium imaging or other signaling assays if TMEM183 is hypothesized to participate in signal transduction

Given that TMEM183 may have developmental roles similar to TMEM182, which affects early stages of myocardial differentiation , researchers should consider temporal expression analyses during cell differentiation models. Additionally, since TMEM183 shows differential expression under altered gravity conditions , mechanical stress assays or altered culture conditions might reveal functional aspects of this protein.

How can researchers effectively analyze TMEM183 expression across tissues and conditions?

For comprehensive analysis of TMEM183 expression, researchers should employ multiple complementary techniques that cover both mRNA and protein levels. A recommended methodological approach includes:

• mRNA expression analysis:

  • Quantitative RT-PCR for targeted, sensitive detection across samples

  • RNA-seq for genome-wide expression context and splice variant detection

  • Single-cell RNA-seq to identify cell-type specific expression patterns

  • In situ hybridization for spatial localization within tissues

• Protein expression analysis:

  • Western blotting for semi-quantitative protein level determination

  • Immunohistochemistry or immunofluorescence for tissue and subcellular localization

  • Proteomics approaches (mass spectrometry) for unbiased protein quantification

  • Flow cytometry for single-cell protein expression in suitable samples

When analyzing expression data from different conditions (such as microgravity or hypergravity as mentioned in search result ), researchers should employ appropriate statistical methods including principal component analysis to identify patterns across multiple experimental variables. For examining differential expression, approaches such as DESeq2 or EdgeR for RNA-seq data have been successfully used in studies of TMEM family genes .

A standardized experimental design should include appropriate housekeeping genes or proteins as internal controls, and validation across multiple biological replicates to account for natural variation in expression levels.

What bioinformatic tools are most useful for analyzing TMEM183 structure and function?

For comprehensive bioinformatic analysis of TMEM183, researchers should utilize a combination of specialized tools targeting different aspects of protein characterization:

• Sequence analysis and evolutionary conservation:

  • Multiple sequence alignment tools (MUSCLE, Clustal Omega, T-Coffee)

  • Phylogenetic analysis software (MEGA, PhyML, MrBayes)

  • ConSurf for mapping conservation onto structural models

• Structural prediction and analysis:

  • TMHMM, HMMTOP, or Phobius for transmembrane domain prediction

  • I-TASSER, AlphaFold2, or SWISS-MODEL for 3D structure prediction

  • PyMOL or UCSF Chimera for structural visualization and analysis

• Functional prediction:

  • InterProScan for domain and motif identification

  • NetPhos or GPS for phosphorylation site prediction

  • STRING or GeneMANIA for protein-protein interaction network prediction

Given the transmembrane nature of TMEM183, special attention should be paid to membrane topology prediction using consensus approaches that combine multiple algorithms. Researchers should also consider homology-based function prediction by comparing TMEM183 to better-characterized family members like TMEM182, which has documented roles in cellular differentiation pathways .

When interpreting bioinformatic predictions, researchers should remain mindful of the limitations of each tool and validate key findings experimentally whenever possible, particularly for novel or poorly characterized proteins like TMEM183.

How should researchers approach contradictory data when studying novel proteins like TMEM183?

When confronted with contradictory data during TMEM183 research, a systematic troubleshooting and reconciliation approach is recommended:

• Methodological validation:

  • Verify reagent specificity (especially antibodies) through appropriate controls

  • Assess experimental conditions that might influence results (cell types, expression levels)

  • Replicate experiments using alternative techniques to measure the same parameter

• Biological context consideration:

  • Evaluate whether contradictions might represent genuine biological variance

  • Consider developmental timing, cell-specific effects, or species differences

  • Examine whether post-translational modifications might explain functional differences

• Integration strategies:

  • Develop testable hypotheses that might explain apparent contradictions

  • Design experiments specifically to address discrepancies

  • Consider whether contradictory findings might represent different aspects of a complex function

For instance, if studies show opposing effects of TMEM183 in different cell types, this might reflect genuine biological differences in protein interaction networks or signaling contexts. Similar to TMEM182, which specifically affects early stages of differentiation but not later stages , TMEM183 might have context-dependent functions that appear contradictory when studied in isolation.

When publishing research on novel proteins like TMEM183, transparent reporting of contradictory findings and thoughtful discussion of potential explanations advances the field more effectively than selective reporting of consistent results.

What are the most promising future research directions for TMEM183?

Based on current knowledge about TMEM183 and related proteins, several promising research directions emerge for advancing understanding of this protein:

• Comprehensive characterization across primate species:

  • Comparative genomics and expression analyses between human and non-human primate TMEM183

  • Functional evolution studies to identify conserved and divergent roles

• Mechanistic studies in developmental and cellular processes:

  • Investigation of potential roles in cellular differentiation, similar to TMEM182's function in myocardial differentiation

  • Exploration of TMEM183's function in response to mechanical forces, based on its differential expression under altered gravity conditions

• Disease relevance and therapeutic potential:

  • Examination of expression patterns in various pathological conditions

  • Assessment of potential as a biomarker or therapeutic target, particularly if functional studies suggest roles in clinically relevant pathways

• Integration into broader cellular networks:

  • Systematic protein interaction mapping to place TMEM183 in cellular signaling networks

  • Multi-omics approaches to understand how TMEM183 coordinates with other cellular components

Researchers should prioritize establishing fundamental aspects of TMEM183 biology while remaining open to unexpected functions that may emerge during investigation. The relatively limited current knowledge about this protein presents both challenges and opportunities for novel discoveries that could significantly advance understanding of transmembrane protein biology.

What are the key challenges in translating basic TMEM183 research to potential applications?

Translating fundamental research on TMEM183 to practical applications faces several significant challenges that researchers should anticipate and address:

• Functional redundancy and compensation:

  • Closely related TMEM family proteins may compensate for TMEM183 manipulation

  • Partial functional overlap may obscure phenotypes in knockout models

  • Development of highly specific targeting approaches is essential

• Technical challenges of membrane protein research:

  • Difficulty in obtaining high-resolution structural data

  • Challenges in developing specific antibodies or small molecule modulators

  • Complexity of studying membrane proteins in their native lipid environment

• Bridging model systems and human relevance:

  • Validating findings from non-human primates like Pongo abelii in human systems

  • Accounting for species-specific differences in expression and function

  • Developing appropriate human cell or organoid models

• Multifunctional nature of many transmembrane proteins:

  • Potential for pleiotropic effects when targeting TMEM183

  • Need for tissue-specific or context-specific targeting strategies

  • Complex interpretation of phenotypes resulting from manipulation