SERTAD2 Human

What are the known synonyms and basic characteristics of human SERTAD2?

SERTAD2 is also known as Transcriptional regulator interacting with the PHD-bromodomain 2 (TRIP-Br2), KIAA0127, and Sei-2. The human SERTAD2 protein contains 337 amino acids with a molecular mass of approximately 36.3 kDa . It belongs to the SERTAD family of proteins that contain the SERTA domain. The gene is located on chromosome 2 in humans and encodes a protein that functions as a transcriptional coregulator .

Methodological approach: When conducting research on SERTAD2, it's important to search literature using all known synonyms to ensure comprehensive coverage. Protein identification can be confirmed using western blotting with specific antibodies against SERTAD2 or through mass spectrometry analysis. For gene expression studies, primers should be designed to unique regions that distinguish SERTAD2 from its paralogs, particularly CDCA4 .

What is the subcellular localization and tissue distribution of SERTAD2?

SERTAD2 is primarily localized in the nucleoplasm and cytosol, consistent with its role as a transcriptional regulator . According to protein atlas data, SERTAD2 is expressed across multiple tissues including the brain, adipose tissue, and various organs . Notably, its expression in adipose tissue shows a depot-specific pattern, with higher expression in visceral fat compared to subcutaneous fat in obesity conditions .

Methodological approach: To study subcellular localization, immunofluorescence microscopy using specific antibodies or expression of tagged SERTAD2 (GFP or FLAG) can be employed. For tissue distribution analysis, qRT-PCR and western blotting of tissue lysates are recommended, with appropriate housekeeping genes or proteins as controls. When examining adipose tissue, it's critical to separate mature adipocytes from stromal vascular fraction to determine cell type-specific expression .

How does SERTAD2 expression change in obesity, and what mechanisms regulate its expression?

SERTAD2 is specifically upregulated in visceral fat but not subcutaneous fat in obese individuals . Its expression is regulated by endoplasmic reticulum (ER) stress, which is elevated in visceral adipose tissue during obesity. Various factors can induce SERTAD2 expression in adipocytes, including:

• Conditioned media from mature adipocytes isolated from high-fat diet (HFD)-fed mice

• Proinflammatory cytokines produced by activated macrophages

• ER stress inducers such as tunicamycin

Methodological approach: To study SERTAD2 regulation in obesity:

• Use paired visceral and subcutaneous adipose tissue samples

• Employ both in vivo models (HFD-fed mice) and in vitro systems (3T3-L1 or SGBS human adipocytes)

• Apply ER stress inducers (tunicamycin, thapsigargin) and inhibitors (TUDCA)

• Monitor ER stress markers (XBP1 splicing, CHOP, GRP78) alongside SERTAD2 expression

• Validate findings through both mRNA and protein measurements

What role does SERTAD2 play in adipocyte metabolism and fat storage?

SERTAD2 modulates fat storage by downregulating the expression of key genes involved in:

• Adipocyte lipolysis

• Thermogenesis

• Oxidative metabolism

Studies using TRIP-Br2 (SERTAD2) knockout mice have demonstrated that ablation of this gene protects mice from obesity and associated metabolic dysfunction. SERTAD2 appears to be a critical molecular mediator for ER stress-induced inflammatory and acute phase responses in visceral fat .

Methodological approach: To investigate SERTAD2's metabolic functions:

• Use gene silencing (siRNA) or overexpression in adipocyte cell lines

• Measure lipolysis rates via glycerol release assays

• Assess oxygen consumption rates to determine mitochondrial function

• Perform transcriptional profiling of metabolic genes

• Validate in vivo using tissue-specific knockout models

• Examine inflammatory markers (IL-6, MCP1) in circulation and tissue

How does SERTAD2 contribute to tumorigenesis, particularly in lung cancer?

SERTAD2 is overexpressed in various human tumors and promotes tumorigenesis in nude mice. In lung cancer specifically, REV1 (a translesion DNA synthesis polymerase) upregulates SERTAD2 expression in a Rad18-dependent manner, thereby promoting lung carcinogenesis . The REV1-Rad18-SERTAD2 axis represents a potential therapeutic target for lung cancer.

Table 1: SERTAD2 Regulation and Function in Lung Cancer

Methodological approach: To study SERTAD2 in cancer:

• Compare SERTAD2 expression in tumor vs. adjacent normal tissues

• Perform survival analysis based on SERTAD2 expression levels

• Use RNA interference to assess functional impact on proliferation, migration, and colony formation

• Investigate transcriptional targets through ChIP-seq and RNA-seq following SERTAD2 manipulation

• Test inhibitors of the REV1-Rad18-SERTAD2 pathway in preclinical models

What transcriptional targets and mechanisms mediate SERTAD2's effects in cancer cells?

SERTAD2 acts at E2F-responsive promoters as a coregulator that integrates signals provided by PHD- and bromodomain-containing transcription factors. It can function as both a coactivator and corepressor of E2F1-TFDP1 and E2F4-TFDP1 complexes on E2F consensus binding sites, thereby activating or inhibiting E2F-target genes expression . These E2F target genes are often involved in cell cycle regulation, DNA replication, and apoptosis, which explains SERTAD2's role in cancer progression.

Methodological approach: To identify SERTAD2 transcriptional targets:

• Perform ChIP-seq to map SERTAD2 binding sites genome-wide

• Conduct RNA-seq after SERTAD2 knockdown/overexpression to identify regulated genes

• Use reporter assays with E2F-responsive elements to assess transcriptional activity

• Investigate protein-protein interactions with E2F family members and associated cofactors

• Employ proteomics approaches to identify SERTAD2 complexes in different cellular contexts

What are the best experimental systems for studying SERTAD2 function?

Various experimental systems can be employed to study SERTAD2, each with specific advantages:

• Cell lines:

  • 3T3-L1 adipocytes for metabolic studies

  • SGBS human adipocytes for translational relevance

  • Lung cancer cell lines (based on endogenous SERTAD2 expression levels)

  • Immortalized adipocyte cell lines from different fat depots

• Animal models:

  • Global SERTAD2/TRIP-Br2 knockout mice

  • Tissue-specific conditional knockout models

  • High-fat diet-induced obesity models

  • Xenograft models for cancer studies

• Human samples:

  • Paired visceral and subcutaneous adipose tissues

  • Tumor-normal paired samples from cancer patients

Methodological approach: Selection of the appropriate model system should be based on:

• The specific aspect of SERTAD2 biology being investigated

• Tissue/cell type relevance

• Need for in vivo physiological context

• Requirement for human clinical relevance

• Availability of tools for genetic manipulation

What are the challenges in producing and working with recombinant SERTAD2 protein?

Producing functional recombinant SERTAD2 presents several challenges:

• SERTAD2 human recombinant protein can be produced in E. coli as a single, non-glycosylated polypeptide chain .

• Stabilization typically requires:

  • Appropriate buffer conditions (20mM Tris-HCl buffer pH 8.0, 0.15M NaCl, 10% glycerol, 1mM DTT)

  • Addition of carrier proteins (0.1% HSA or BSA) for long-term storage

  • Avoiding multiple freeze-thaw cycles

• Purification can be achieved through proprietary chromatographic techniques, often facilitated by an N-terminal His-tag .

Methodological approach: For functional studies with recombinant SERTAD2:

• Consider testing different expression systems (E. coli, insect cells, mammalian cells)

• Include appropriate tags (His, GST, FLAG) for purification while confirming they don't interfere with function

• Validate protein folding and activity through functional assays

• Ensure storage in appropriate buffer conditions to maintain stability

• Consider expressing specific domains separately for structure-function analyses

How do we resolve contradictory data regarding SERTAD2's tissue-specific regulation and function?

Research on SERTAD2 has revealed seemingly contradictory findings regarding its regulation and function in different contexts. For example, SERTAD2 shows depot-specific expression and regulation in adipose tissue, with significant upregulation in visceral but not subcutaneous fat in response to ER stress . Additionally, different experimental systems may yield varying results regarding the role of mature adipocytes versus stromal-vascular fraction in regulating SERTAD2 expression.

Methodological approach to resolve contradictions:

• Use multiple experimental systems and approaches to validate findings

• Consider tissue/cell type-specific effects and context-dependent regulation

• Examine temporal dynamics of SERTAD2 expression and function

• Control for experimental variables such as isolation methods that may affect cell populations

• Validate in vitro findings with in vivo models

• Consider species differences when translating between mouse and human systems

For example, when addressing contradictory results between conditioned media experiments and in vivo observations, factors such as macrophage activation state, cytokine stability, and cell isolation methods should be considered .

What are the emerging therapeutic opportunities targeting SERTAD2 pathways?

Based on current understanding, several therapeutic opportunities targeting SERTAD2 pathways are emerging:

• In metabolic disease:

  • ER stress modulators to regulate SERTAD2 expression in visceral fat

  • Anti-inflammatory agents to disrupt the inflammation-SERTAD2 vicious cycle

  • Direct SERTAD2 inhibitors to improve metabolic parameters in obesity

• In cancer:

  • REV1 inhibitors (e.g., JH-RE-06) that indirectly reduce SERTAD2 expression

  • Targeted approaches to disrupt SERTAD2 interactions with E2F factors

  • Combination therapies targeting both SERTAD2 and related pathway components

Methodological approach for therapeutic development:

• Perform high-throughput screening for direct SERTAD2 inhibitors

• Develop assays to measure disruption of protein-protein interactions

• Test candidates in relevant disease models (obesity, cancer)

• Assess tissue-specific delivery systems

• Evaluate combination approaches with existing therapies

• Consider biomarker development for patient stratification

What are the most pressing unanswered questions about SERTAD2 biology?

Despite significant progress, several key questions remain about SERTAD2 biology:

• What is the three-dimensional structure of SERTAD2 and how does it interact with binding partners?

• What is the complete set of transcriptional targets of SERTAD2 in different cellular contexts?

• How do post-translational modifications regulate SERTAD2 function?

• What is the evolutionary conservation of SERTAD2 function across species?

• Are there additional physiological roles for SERTAD2 beyond metabolism and cancer?

• What is the potential role of SERTAD2 in other disease contexts such as neurodegenerative disorders or immune dysfunction?

Methodological approach for future research:

• Apply emerging technologies (cryo-EM, single-cell approaches, spatial transcriptomics)

• Develop more sophisticated animal models with tissue-specific and inducible expression

• Establish clinical collaborations to collect relevant human samples

• Integrate multi-omics approaches to comprehensively map SERTAD2 functions

By addressing these questions through rigorous scientific investigation, researchers can advance our understanding of SERTAD2 biology and potentially develop novel therapeutic strategies for related diseases.