SEC62 Antibody

What is SEC62 and what cellular functions does it perform?

SEC62 is an integral endoplasmic reticulum (ER) membrane protein that forms a dimeric complex with SEC63, playing a central role in the translocation of nascent and newly synthesized precursor polypeptides into the ER . This protein is critical for maintaining and recovering ER homeostasis through several mechanisms, including activating the IRE1α-JNK pathway and facilitating the delivery of autophagosomes to lysosomes . SEC62 contains a conserved LC3-interacting region (LIR) that enables it to function as an ER membrane-associated autophagy receptor, promoting the delivery of select ER domains to autolysosomes for degradation . This dual functionality in protein translocation and autophagy regulation positions SEC62 as a key player in cellular stress responses, particularly during conditions that challenge ER homeostasis.

What are the molecular characteristics of SEC62 protein that researchers should be aware of?

SEC62 has several notable molecular characteristics researchers should consider when designing experiments. The protein has a calculated molecular weight of 46 kDa, though it is typically observed at approximately 52 kDa in western blot analyses due to post-translational modifications . The human SEC62 gene corresponds to GenBank accession number NM_003262 with gene ID 7095 (NCBI), and its protein product is identified by UNIPROT ID Q99442 . Structurally, SEC62 contains ER-resident LC3-interacting regions, which are crucial for its function in autophagy-related processes . These molecular features are important when selecting appropriate antibodies and designing experimental controls, as they influence protein detection and functional analysis outcomes.

How does SEC62 contribute to autophagy and ER stress regulation?

SEC62 serves as a critical link between ER stress and autophagy through multiple mechanisms. Research has demonstrated that SEC62 promotes IRE1α phosphorylation and activates the IRE1α-JNK pathway, which enhances autophagic activity and helps maintain ER homeostasis . During cellular stress, SEC62 can physically interact with LC3 through its LIR domain, facilitating the recruitment of autophagosomes to areas of the ER requiring clearance . In a study involving foot-and-mouth disease virus (FMDV) infection, SEC62 was shown to promote autophagosome formation and delivery to lysosomes, thus relieving ER stress and contributing to viral clearance . The protein's expression levels were found to increase slightly during early stages of cellular stress but decrease dramatically in later stages, suggesting a dynamic regulatory role that changes during the progression of stress responses .

What are the recommended applications and dilutions for SEC62 antibody in laboratory research?

Based on validated research protocols, the SEC62 antibody (such as Proteintech's 28693-1-AP) has been successfully applied in several experimental techniques. For Western Blot (WB) applications, the recommended dilution range is 1:1000-1:6000, with optimal results often achieved at mid-range dilutions . For immunofluorescence (IF) and immunocytochemistry (ICC) applications, dilutions between 1:200-1:800 are recommended . The antibody has been positively tested in WB applications using HT-29 and SW480 cells, while IF/ICC applications have been validated in HepG2 cells . It's important to note that optimal dilutions may be sample-dependent, and researchers are advised to perform titration experiments in their specific testing systems to determine optimal conditions. The antibody has also been successfully used in ELISA applications, though specific dilution recommendations for this technique are not provided in the available literature .

What cell lines and experimental models have been validated for SEC62 antibody applications?

Several cell lines have been validated for SEC62 antibody applications in different experimental contexts. For western blot analysis, HT-29 and SW480 colorectal cancer cell lines have shown positive results . For immunofluorescence studies, HepG2 hepatocellular carcinoma cells have demonstrated reliable detection of SEC62 . In functional studies investigating SEC62's role in colorectal cancer metastasis, researchers have successfully manipulated SEC62 expression in HCT116, Caco-2, DLD-1, and SW480 colorectal cancer cell lines . For gastric cancer research, immunofluorescence protocols have been established using SEC62 antibodies in conjunction with other markers such as E-cadherin, vimentin, LC3, and FLAG-tagged proteins . Additionally, PK-15 cells have been used in studies examining SEC62's role in autophagy and viral infection responses . These validated cell lines provide researchers with reliable experimental models for studying SEC62 expression and function across different tissue types and disease contexts.

How can researchers optimize colocalization studies involving SEC62 and autophagy markers?

For optimal colocalization studies examining SEC62's interactions with autophagy markers such as LC3, researchers should follow several methodological considerations. First, cells should be carefully fixed with 4% paraformaldehyde for 10 minutes, followed by PBS washing and blocking with fetal bovine serum for 60 minutes at room temperature . Primary antibodies against SEC62 and LC3 should be incubated overnight at 4°C, followed by appropriate secondary antibody incubation . For quantitative analysis of colocalization, Image-Pro Plus version 6.0 software with Manders Overlap Coefficient (MOC) with background correction has been successfully employed . In co-immunoprecipitation assays examining SEC62-LC3 interactions, researchers have successfully used both overexpressed tagged proteins (FLAG-Sec62 and GFP-LC3) and endogenous protein detection approaches . These studies have revealed that SEC62 physically interacts with LC3 through its LIR domain, and this interaction increases during cellular stress conditions. Careful selection of antibody combinations that do not cross-react and optimization of fixation conditions are crucial for reliable results.

What evidence indicates SEC62's involvement in cancer progression and metastasis?

Substantial evidence links SEC62 to cancer progression and metastasis across multiple cancer types. Clinical studies have revealed that SEC62 is significantly upregulated in colorectal cancer tissues compared to adjacent normal tissues, with expression levels positively correlating with poor prognosis . Statistical analysis of patient data has demonstrated significant associations between high SEC62 expression and several clinicopathological features, including larger tumor size (p=0.03), lymph node metastasis (p=0.017), and advanced AJCC stage (p=0.010) . The table below summarizes these clinical correlations:

Beyond colorectal cancer, SEC62 is associated with poor prognosis in prostate cancer, hepatocellular cancer, breast cancer, melanoma, and gastric cancer . These findings collectively establish SEC62 as an important biomarker and potential therapeutic target in multiple cancer types.

How does SEC62 mechanistically contribute to cancer metastasis?

Mechanistic studies have revealed that SEC62 promotes cancer metastasis through multiple pathways. In colorectal cancer, experimental evidence from both in vitro and in vivo studies demonstrates that SEC62 upregulation significantly enhances cancer cell motility, invasion, and migration abilities . Transwell assays with SEC62-overexpressing HCT116 and Caco-2 cells showed markedly increased invasion capacity, while SEC62 knockdown in DLD-1 and SW480 cells significantly reduced their metastatic potential . In animal models, SEC62 overexpression increased the number of metastatic lung nodules, enhanced lung metastasis incidence, and resulted in shortened survival time . At the molecular level, SEC62 appears to drive cancer metastasis partly through its role in unfolded protein response (UPR) regulation and epithelial-to-mesenchymal transition (EMT), which involves changes in E-cadherin and vimentin expression . SEC62's function in autophagy regulation may also contribute to cancer cell adaptation to stress and survival during metastasis. These mechanisms collectively explain how SEC62 overexpression contributes to more aggressive cancer phenotypes and poorer clinical outcomes.

What experimental approaches can be used to study SEC62's function in cancer cells?

Researchers investigating SEC62's role in cancer can employ several well-validated experimental approaches. For modulating SEC62 expression, lentiviral transduction systems have been successfully used both for overexpression (LV-SEC62) and knockdown (shSEC62 constructs) . The efficacy of these genetic manipulations should be confirmed by qRT-PCR and western blot before proceeding with functional studies . Transwell assays and wound healing assays provide reliable methods for assessing changes in cancer cell motility, migration, and invasion following SEC62 expression alteration . For in vivo metastasis studies, mouse models involving tail vein injection of manipulated cancer cells followed by lung metastasis evaluation have proven effective . Co-immunoprecipitation and immunofluorescence co-localization studies can reveal SEC62's interactions with autophagy proteins like LC3, providing insights into its cellular function . Additionally, analyzing clinical samples for SEC62 expression by immunohistochemistry and correlating with patient data offers valuable translational insights. RNA sequencing and proteomics approaches may also be employed to identify SEC62-regulated pathways and potential therapeutic targets.

How does SEC62 interact with the IRE1α-JNK signaling pathway during cellular stress?

Research has uncovered a sophisticated relationship between SEC62 and the IRE1α-JNK signaling pathway that influences cellular stress responses. SEC62 overexpression promotes the phosphorylation of IRE1α, particularly during later stages of cellular stress . This activation subsequently enhances the phosphorylation of downstream molecules JNK and Bcl-2, forming a signaling cascade that regulates autophagy and stress responses . Experimental evidence from Sec62-overexpressed cells shows increased phosphorylation of IRE1α, JNK, and Bcl-2 at 9 hours post-infection, while Sec62-knockdown cells exhibit inhibited phosphorylation of these proteins . Interestingly, activation of this pathway correlates with increased LC3 conversion (an autophagy marker) and decreased viral replication in infection models . These findings suggest that SEC62 serves as an upstream regulator of the IRE1α-JNK pathway, connecting ER stress sensing with autophagy activation. The dose-dependent nature of this relationship has been demonstrated, with increasing SEC62 levels progressively enhancing autophagy development while suppressing viral replication . This mechanism represents a critical cellular defense against stress that may be dysregulated in disease contexts.

What is the significance of SEC62's LC3-interacting region (LIR) in autophagy regulation?

The LC3-interacting region (LIR) of SEC62 plays a crucial role in connecting ER homeostasis with selective autophagy. Coimmunoprecipitation assays have confirmed that SEC62 physically interacts with LC3 through this conserved domain . This interaction is functionally significant as it enables SEC62 to act as a scaffold protein that recruits autophagosomal machinery to specific ER regions requiring clearance . Immunofluorescence assays have demonstrated that SEC62 colocalizes with both LC3 (an autophagosome marker) and LAMP1 (a lysosomal marker), suggesting its involvement in the complete autophagic flux process from autophagosome formation to lysosomal fusion and degradation . The LIR domain's function appears particularly important during recovery from ER stress, allowing for the selective degradation of excess ER components and misfolded proteins through a process called "recovER-phagy" . This selective autophagy mechanism is distinct from bulk autophagy and represents a specialized cellular maintenance system. Understanding the LIR domain's structural requirements and regulatory modifications (such as phosphorylation events that might enhance LC3 binding) represents an important frontier in SEC62 research with implications for both fundamental cell biology and disease interventions.

What storage and handling considerations are critical for maintaining SEC62 antibody effectiveness?

Proper storage and handling of SEC62 antibodies are crucial for maintaining their effectiveness in experimental applications. SEC62 antibodies should be stored at -20°C, where they remain stable for one year after shipment . The storage buffer typically contains PBS with 0.02% sodium azide and 50% glycerol at pH 7.3, which helps maintain antibody stability . For most antibody preparations, aliquoting is unnecessary for -20°C storage, which simplifies laboratory workflows . Some SEC62 antibody preparations in smaller sizes (20μl) contain 0.1% BSA as a stabilizer . Researchers should avoid repeated freeze-thaw cycles, which can lead to antibody degradation and reduced sensitivity. When working with the antibody, it should be thawed completely and mixed gently before use. Diluted working solutions should be prepared fresh before experiments to ensure optimal binding activity. Additionally, researchers should be aware that antibodies containing sodium azide should not be used with horseradish peroxidase (HRP) systems without appropriate washing steps, as sodium azide can inhibit HRP activity. Following these storage and handling guidelines will help ensure consistent and reliable results when using SEC62 antibodies.

How can researchers validate SEC62 antibody specificity for their experimental systems?

Validating SEC62 antibody specificity is essential for generating reliable experimental data. Several approaches can be employed to confirm antibody specificity in particular experimental systems. First, researchers should perform western blot analysis to verify that the antibody detects a protein of the expected molecular weight (approximately 52 kDa for SEC62) . Positive controls using cell lines known to express SEC62 (such as HT-29 or SW480 cells) should be included . For definitive validation, researchers can manipulate SEC62 expression through overexpression or knockdown approaches and confirm corresponding changes in signal intensity . This genetic validation approach is particularly powerful, as it demonstrates specificity under the exact experimental conditions being used. Additionally, peptide competition assays, where the antibody is pre-incubated with the immunizing peptide before staining, can help confirm binding specificity. For immunofluorescence applications, co-staining with antibodies against known ER markers can confirm proper subcellular localization. Multiple antibody validation techniques should be combined when possible, and researchers should be particularly cautious when applying antibodies to novel cell types or experimental conditions not previously validated in the literature.

How might SEC62 serve as a therapeutic target in cancer and other diseases?

SEC62's established roles in cancer progression, ER stress responses, and autophagy regulation position it as a promising therapeutic target worthy of further investigation. Several strategic approaches could exploit SEC62's functions for therapeutic benefit. First, direct targeting of SEC62 through small molecule inhibitors or degraders (PROTACs) could potentially reduce metastatic potential in cancers where SEC62 is overexpressed, including colorectal, gastric, prostate, and hepatocellular cancers . Given SEC62's role in activating the IRE1α-JNK pathway and autophagy during stress, modulating rather than completely inhibiting its function might provide therapeutic benefits in conditions involving ER stress dysregulation . The protein's LC3-interacting region represents a specific structural target that could be exploited to selectively modulate autophagy regulation while potentially preserving other SEC62 functions . Additionally, since SEC62 expression correlates with clinical cancer progression, it could serve as a biomarker for patient stratification in clinical trials . For viral infections where SEC62 helps clear viral particles through autophagy, therapeutic approaches enhancing SEC62 expression or activity might augment host defense mechanisms . As research progresses, combination therapies targeting SEC62 alongside other ER stress or autophagy modulators might provide synergistic benefits in complex diseases involving these cellular processes.

What emerging methodologies might enhance the study of SEC62's roles in cellular homeostasis?

Several emerging technologies and methodologies hold promise for advancing our understanding of SEC62's multifaceted roles in cellular homeostasis. CRISPR-Cas9 genome editing with inducible or tissue-specific promoters could enable more precise temporal and spatial control of SEC62 expression than traditional overexpression or knockdown approaches. Live-cell imaging techniques using fluorescently tagged SEC62 and interaction partners could reveal dynamic relationships between SEC62, the ER, autophagosomes, and lysosomes in real-time during stress responses. Advanced proteomics approaches, including BioID or APEX proximity labeling, could identify novel SEC62 interaction partners under different physiological conditions, potentially uncovering previously unknown functions. Single-cell RNA sequencing of tissues with variable SEC62 expression might reveal cell-type specific responses to SEC62 modulation that are masked in bulk tissue analyses. For structural insights, cryo-electron microscopy could potentially elucidate SEC62's membrane organization and interaction with the translocation machinery and autophagy components. Patient-derived organoids expressing different levels of SEC62 would provide more physiologically relevant models than traditional cell lines for studying its roles in disease processes. These technological advances, combined with computational approaches to integrate multi-omics data, will likely yield more comprehensive models of SEC62's functions in maintaining cellular homeostasis across different tissues and disease states.