STAMBP Human
Description
Introduction to STAM-binding Protein (STAMBP)
STAM-binding protein (STAMBP), also known as AMSH (Associated Molecule with the SH3 domain of STAM), is a deubiquitinating enzyme (DUB) belonging to the JAMM metalloprotease family. It plays critical roles in cellular processes such as endosomal sorting, signal transduction, and ubiquitin-dependent protein regulation. STAMBP specifically cleaves K63-linked polyubiquitin chains but does not act on K48-linked chains, distinguishing it from other DUBs .
Key Functions
Expression Systems and Tags
Stability and Handling
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Storage: Short-term storage at 4°C; long-term storage at -20°C with carrier proteins (e.g., BSA) to prevent aggregation .
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Activity Notes: DTT concentrations >1 mM inhibit GST-tagged STAMBP activity .
Genetic Disorders
Microcephaly-Capillary Malformation Syndrome (MICCAP):
Cancer
Neural Progenitor Cells
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STAMBP Deficiency: Impaired long-term proliferation of neural stem cells (NSCs) due to reduced CFLAR levels (anti-apoptotic protein) .
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Rescue Mechanism: Ectopic CFLAR expression restores NSC proliferation in STAMBP-deficient cells .
Inflammasome Regulation
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NALP7 Stabilization: STAMBP prevents NALP7 degradation, promoting inflammasome activation .
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NLRP3 Regulation: Limits excessive ubiquitination of NLRP3 to avoid hyperinflammatory responses .
Chemotherapy Sensitivity
Product Specs
Q&A
Experimental Design for Studying STAMBP Mutations
Q: How can researchers effectively design experiments to study the impact of STAMBP mutations on human brain development? A: To study STAMBP mutations, researchers can use whole exome sequencing to identify novel mutations, followed by validation using Sanger sequencing. Utilizing human cortical organoids allows for the investigation of STAMBP's role in neural stem cell proliferation and differentiation. This approach helps bridge the gap between mouse models and human diseases by providing a relevant cellular context for studying developmental disorders .
Data Contradiction Analysis in STAMBP Research
Q: How do researchers address contradictions in data regarding the activation of signaling pathways in STAMBP mutations? A: Contradictions in data can arise from differences in experimental models or mutations. For instance, some studies suggest that STAMBP mutations lead to the activation of the RAS-MAPK and PI3K-AKT-mTOR pathways, while others fail to replicate these findings. Researchers should consider the specific mutation and model used, as different mutations may affect different pathways, leading to variable clinical phenotypes .
Advanced Research Questions: STAMBP and Microcephaly
Q: What are the advanced research questions regarding the relationship between STAMBP mutations and microcephaly? A: Advanced research questions include understanding how STAMBP mutations disrupt neural stem cell proliferation without significantly affecting apoptosis in early cortical development. Additionally, investigating why microcephaly is not recapitulated in mouse models despite being a common phenotype in humans with STAMBP mutations is crucial. This involves comparing human organoid models with animal studies to elucidate the pathophysiological mechanisms involved .
Methodological Approaches for STAMBP Expression Analysis
Q: What methodological approaches can researchers use to analyze STAMBP expression during human brain development? A: Researchers can analyze STAMBP expression by generating human cortical organoids from pluripotent stem cells. Techniques such as RT-PCR can be used to quantify STAMBP mRNA levels at different developmental stages. Immunofluorescence staining for markers like SOX2, PAX6, and NeuN helps confirm the differentiation status of neural cells in organoids .
Rescue Experiments for STAMBP Mutations
Q: How can researchers design rescue experiments to study the pathogenicity of specific STAMBP mutations? A: Rescue experiments involve re-expressing wild-type or mutant STAMBP in knockout organoids. For example, using CRISPR-Cas9 to knock out STAMBP and then re-expressing it with specific mutations (e.g., G307E) can help determine if the mutation impairs neural stem cell proliferation. This approach allows researchers to assess the functionality of different mutations in a controlled manner .
Comparative Analysis of Human and Mouse Models
Q: What are the key differences between human and mouse models in studying STAMBP mutations? A: Human models, such as brain organoids, are crucial for studying STAMBP mutations because they more accurately reflect human disease phenotypes compared to mouse models. Mouse models often fail to replicate congenital phenotypes seen in humans, such as microcephaly, highlighting the need for human-specific models to understand the pathophysiology of STAMBP-related disorders .
Informed Consent in STAMBP Research
Q: How should researchers ensure informed consent in studies involving human subjects with STAMBP mutations? A: Ensuring informed consent involves using IRB-approved consent forms that clearly explain the purpose, risks, and benefits of the research. Researchers must consider the participant's understanding, language, and any special needs. Informed consent is an ongoing process, especially in longitudinal studies, and should be tailored to the specific participant population .
Data Storage and Security in STAMBP Research
Q: What guidelines should researchers follow for data storage and security in studies involving human subjects with STAMBP mutations? A: Researchers should store data securely on approved servers or platforms like SharePoint or NetApp. Data collection and storage should comply with federal regulations and institutional policies to protect participant privacy. Ensuring data integrity and confidentiality is crucial in human subjects research .
STAMBP and Endosomal Sorting Complexes
Q: How does STAMBP interact with endosomal sorting complexes required for transport (ESCRTs)? A: STAMBP interacts with ESCRTs to facilitate the endocytosis and sorting of proteins into multivesicular bodies, which are then delivered to lysosomes for degradation. This interaction is crucial for maintaining cellular protein balance and proper cellular function .
Future Directions in STAMBP Research
Q: What are some future directions for research on STAMBP mutations and their impact on human health? A: Future research should focus on elucidating the specific mechanisms by which different STAMBP mutations affect signaling pathways and neural development. Additionally, exploring therapeutic strategies to rescue or mitigate the effects of STAMBP mutations in human diseases is essential. This may involve developing targeted therapies based on insights from organoid models and clinical studies .
Data Table: STAMBP Mutations and Clinical Phenotypes
Product Science Overview
STAM Binding Protein (STAMBP), also known as AMSH (Associated Molecule with the SH3 domain of STAM), is a protein encoded by the STAMBP gene located on chromosome 2p13.1 . This gene is conserved across various species, including chimpanzees, Rhesus monkeys, dogs, cows, mice, rats, chickens, zebrafish, fruit flies, mosquitoes, and frogs .
STAMBP belongs to the JAMM (JAB1/MPN/Mov34 metalloenzyme) family of deubiquitinating enzymes . It contains a microtubule-interacting/transport domain and a STAM-binding domain . The recombinant human STAMBP protein is typically expressed in baculovirus-infected insect cells and is often tagged with a His-tag for purification purposes .
STAMBP plays a critical role in cytokine-mediated signaling for MYC induction and cell cycle progression . It binds to the SH3 domain of the signal-transducing adaptor molecule (STAM) and is involved in the endosomal sorting complex required for transport (ESCRT) pathway . This pathway is essential for the sorting of ubiquitinated proteins into multivesicular bodies, which are then directed to lysosomes for degradation .
As a deubiquitinating enzyme, STAMBP removes ubiquitin molecules from substrate proteins, thereby regulating their stability and function . This activity is zinc-dependent and is crucial for maintaining cellular homeostasis . Mutations in the STAMBP gene can lead to various disorders, including microcephaly-capillary malformation syndrome, a congenital and neurodevelopmental disorder .
STAMBP is widely expressed in various tissues, including the thyroid and brain . Its expression and activity are tightly regulated to ensure proper cellular function. Dysregulation of STAMBP has been implicated in several diseases, including cancer . For instance, STAMBP has been shown to regulate melanoma metastasis through the stabilization of the transcription factor Slug .
