Podcast
Questions and Answers
Which modification ensures proper Wnt protein secretion?
Which modification ensures proper Wnt protein secretion?
- Methylation
- Ubiquitination
- Phosphorylation
- Glycosylation (correct)
What role do Wnt proteins play in Wnt signaling?
What role do Wnt proteins play in Wnt signaling?
- They act as receptors.
- They act as structural proteins.
- They act as ligands. (correct)
- They act as enzymes.
What is the primary function of Wnt signaling during embryonic development?
What is the primary function of Wnt signaling during embryonic development?
- Controlling segment polarity and body axis formation (correct)
- Regulating nutrient supply to the embryo
- Developing the nervous system
- Establishing the circulatory system
Which component directly binds to Wnt proteins to initiate the Wnt signaling pathway?
Which component directly binds to Wnt proteins to initiate the Wnt signaling pathway?
What is the ultimate effect of Wnt signaling on transcription?
What is the ultimate effect of Wnt signaling on transcription?
Which of the following must occur for β-catenin to accumulate and enter the nucleus?
Which of the following must occur for β-catenin to accumulate and enter the nucleus?
What complex does β-catenin form in the nucleus to activate Wnt target genes?
What complex does β-catenin form in the nucleus to activate Wnt target genes?
What event directly precedes β-catenin's entry into the nucleus during Wnt signaling?
What event directly precedes β-catenin's entry into the nucleus during Wnt signaling?
Which of the following is a characteristic of Wnt proteins?
Which of the following is a characteristic of Wnt proteins?
What is the result of Wnt stimulation on cytoplasmic YAP/TAZ?
What is the result of Wnt stimulation on cytoplasmic YAP/TAZ?
Which of the following does the data suggest is a function of YAP/TAZ in Wnt OFF conditions?
Which of the following does the data suggest is a function of YAP/TAZ in Wnt OFF conditions?
Deficiency in which protein is associated with decreased β-TrCP in the destruction complex?
Deficiency in which protein is associated with decreased β-TrCP in the destruction complex?
How does the model propose Yap and Taz function in the absence of Wnt signals?
How does the model propose Yap and Taz function in the absence of Wnt signals?
When Axin1 is depleted, where do YAP/TAZ localize?
When Axin1 is depleted, where do YAP/TAZ localize?
What key insight was revealed regarding Axin1's binding partners?
What key insight was revealed regarding Axin1's binding partners?
How does Wnt stimulation affect the association between YAP/TAZ and Axin1?
How does Wnt stimulation affect the association between YAP/TAZ and Axin1?
According to current research, which factor modulates both the Wnt and Hippo signaling pathways?
According to current research, which factor modulates both the Wnt and Hippo signaling pathways?
Which of the following diseases is NOT directly associated with mutations in Wnt pathway components?
Which of the following diseases is NOT directly associated with mutations in Wnt pathway components?
Which process involving GSK3β is integral to Wnt signaling?
Which process involving GSK3β is integral to Wnt signaling?
How does raising the dose of LRP6 experimentally affect the interaction of Axin1 with YAP/TAZ in Wnt-ON cells?
How does raising the dose of LRP6 experimentally affect the interaction of Axin1 with YAP/TAZ in Wnt-ON cells?
In the experiment with mice injected with tamoxifen, what was the observed outcome when the Villin-CreERT2;Apcfl/fl mice became moribund?
In the experiment with mice injected with tamoxifen, what was the observed outcome when the Villin-CreERT2;Apcfl/fl mice became moribund?
What does the presence of active Wnt signaling in crypt cells contribute to in the intestinal epithelium model?
What does the presence of active Wnt signaling in crypt cells contribute to in the intestinal epithelium model?
How do YAP/TAZ affect tumor suppression?
How do YAP/TAZ affect tumor suppression?
What has been identified as a key step in the carcinogenesis of colorectal cancer (CRC)?
What has been identified as a key step in the carcinogenesis of colorectal cancer (CRC)?
What method was used to determine that Axin1 binds to endogenous YAP and TAZ?
What method was used to determine that Axin1 binds to endogenous YAP and TAZ?
In which cellular compartment is YAP mostly found in confluent and untreated cells?
In which cellular compartment is YAP mostly found in confluent and untreated cells?
How does Axin1 impact Yap and Taz?
How does Axin1 impact Yap and Taz?
Why are YAP and TAZ defined as crucial for cell reprogramming?
Why are YAP and TAZ defined as crucial for cell reprogramming?
How does the first finding for the Wnt pathway lead to its characterization?
How does the first finding for the Wnt pathway lead to its characterization?
What type of mammalian genomes harbor Wnt genes and how many?
What type of mammalian genomes harbor Wnt genes and how many?
What can co-receptors govern in Wnt signaling molecules?
What can co-receptors govern in Wnt signaling molecules?
In cell culture, what do you need when using Matrigel as it relates to the experiment?
In cell culture, what do you need when using Matrigel as it relates to the experiment?
How does glycosylation contribute to the function of Wnt proteins?
How does glycosylation contribute to the function of Wnt proteins?
What is the significance of palmitoylation for Wnt proteins?
What is the significance of palmitoylation for Wnt proteins?
How does Wnt signaling influence embryonic development?
How does Wnt signaling influence embryonic development?
Which role does the Frizzled family of receptors play in Wnt signaling?
Which role does the Frizzled family of receptors play in Wnt signaling?
What is the role of Dishevelled (Dsh) in the Wnt signaling pathway?
What is the role of Dishevelled (Dsh) in the Wnt signaling pathway?
How does glycogen synthase kinase 3 beta (GSK3β) participate in the Wnt signaling pathway?
How does glycogen synthase kinase 3 beta (GSK3β) participate in the Wnt signaling pathway?
What is the consequence of β-catenin entering the nucleus during Wnt signaling?
What is the consequence of β-catenin entering the nucleus during Wnt signaling?
What describes the relationship between Wnt genes and cancer?
What describes the relationship between Wnt genes and cancer?
Which of the following is a key insight in Wnt action gained from studying various model organisms and cell lines?
Which of the following is a key insight in Wnt action gained from studying various model organisms and cell lines?
Which of the following is a function of PORCN (Porcupine) enzyme in Wnt signaling?
Which of the following is a function of PORCN (Porcupine) enzyme in Wnt signaling?
What is essential for the transport and secretion of Wnt proteins by the Porcupine (Porc) enzyme?
What is essential for the transport and secretion of Wnt proteins by the Porcupine (Porc) enzyme?
What process involving Evi/Wntless endosomal vesicles is vital for Wnt secretion?
What process involving Evi/Wntless endosomal vesicles is vital for Wnt secretion?
How does Wnt stimulation affect Axin1 regarding YAP/TAZ association?
How does Wnt stimulation affect Axin1 regarding YAP/TAZ association?
Which mechanism has been identified to explain how Wnt signaling inactivation can be treated?
Which mechanism has been identified to explain how Wnt signaling inactivation can be treated?
According to Figure3A from the content, where are YAP and TAZ expressed in the intestinal environment?
According to Figure3A from the content, where are YAP and TAZ expressed in the intestinal environment?
What is correct about how intestinal stem cells replenish the tissue?
What is correct about how intestinal stem cells replenish the tissue?
How and why can Wnt signaling be beneficial?
How and why can Wnt signaling be beneficial?
What is correct regarding AXIN1?
What is correct regarding AXIN1?
What can you say regarding a cell in the absence of AXIN1?
What can you say regarding a cell in the absence of AXIN1?
In quiescent cells, how does YAP/TAZ effect β-catenin
In quiescent cells, how does YAP/TAZ effect β-catenin
How do secondary messengers drive their function in Wnt signal trasnduction?
How do secondary messengers drive their function in Wnt signal trasnduction?
How would the functional role of YAP and TAZ need to adapt if it were in a Wnt stimulation environment?
How would the functional role of YAP and TAZ need to adapt if it were in a Wnt stimulation environment?
How can the research that combines genetic techniques determine the function of YAP and TAZ?
How can the research that combines genetic techniques determine the function of YAP and TAZ?
What is a common characteristic of tissue that has concerted activation and restriction of distinct gene-expression programs?
What is a common characteristic of tissue that has concerted activation and restriction of distinct gene-expression programs?
How could LRP6 doses play a role in Wnt-ON cells?
How could LRP6 doses play a role in Wnt-ON cells?
What is a direct cause for colorectal cancer?
What is a direct cause for colorectal cancer?
When can a tissue follow to homeostasis and regeneration?
When can a tissue follow to homeostasis and regeneration?
What were used to show that YAP and TAZ are integral components of the b-catenin destruction complex and Wnt signaling?
What were used to show that YAP and TAZ are integral components of the b-catenin destruction complex and Wnt signaling?
In a Wnt-OFF state, where are YAP/TAZ primarily located within the cell, and what is their function?
In a Wnt-OFF state, where are YAP/TAZ primarily located within the cell, and what is their function?
A cell undergoing Wnt stimulation experiences a shift in YAP/TAZ function. What is the subsequent effect of YAP/TAZ?
A cell undergoing Wnt stimulation experiences a shift in YAP/TAZ function. What is the subsequent effect of YAP/TAZ?
What function does the Retromer perform during Wnt secretion?
What function does the Retromer perform during Wnt secretion?
How does Axin1 contribute to tumor suppression?
How does Axin1 contribute to tumor suppression?
A laboratory is investigating the effects of a novel drug on Wnt signaling in colorectal cancer cells. How could they leverage genome editing?
A laboratory is investigating the effects of a novel drug on Wnt signaling in colorectal cancer cells. How could they leverage genome editing?
YAP and TAZ nuclear localization in the crypt has been determined to be which of the following?
YAP and TAZ nuclear localization in the crypt has been determined to be which of the following?
A recent experiment was investigating the effects of Villin on mouse. What could have been a sign that can be expected to be observed?
A recent experiment was investigating the effects of Villin on mouse. What could have been a sign that can be expected to be observed?
Two sets of mice have been injected by tamoxifen, one has been initially sacrificed, what conclusion can you make?
Two sets of mice have been injected by tamoxifen, one has been initially sacrificed, what conclusion can you make?
To what extent are the triple mutant mice still alive or do they show signs of aberrant crypt hyperplasia after three weeks?
To what extent are the triple mutant mice still alive or do they show signs of aberrant crypt hyperplasia after three weeks?
A scientist is working with Matrigel and is seeking essential conditions for crypt maintenance and growth. What should they do?
A scientist is working with Matrigel and is seeking essential conditions for crypt maintenance and growth. What should they do?
If Tamoxifen is introduced in Wnt related experiments, what can then be predicted for the mutant crypts?
If Tamoxifen is introduced in Wnt related experiments, what can then be predicted for the mutant crypts?
What developmental process is influenced by Wnt's control over segment polarity?
What developmental process is influenced by Wnt's control over segment polarity?
How does Wnt protein palmitoylation contribute to its function?
How does Wnt protein palmitoylation contribute to its function?
What is the immediate effect of Wnt protein binding to Frizzled receptors?
What is the immediate effect of Wnt protein binding to Frizzled receptors?
How do co-receptors influence Wnt signaling pathways?
How do co-receptors influence Wnt signaling pathways?
What is the role of Evi/Wntless in Wnt secretion?
What is the role of Evi/Wntless in Wnt secretion?
How can Wnt signaling lead to carcinogenesis in colorectal cancer (CRC)?
How can Wnt signaling lead to carcinogenesis in colorectal cancer (CRC)?
What is the primary role of beta-catenin in the Wnt signaling pathway?
What is the primary role of beta-catenin in the Wnt signaling pathway?
When Wnt is absent, what is the state of β-catenin?
When Wnt is absent, what is the state of β-catenin?
What causes the functional inactivation of the destruction complex?
What causes the functional inactivation of the destruction complex?
What is the consequence of TCF binding to Groucho in the Wnt pathway?
What is the consequence of TCF binding to Groucho in the Wnt pathway?
Based on the research paper, what is the relationship between YAP/TAZ and beta-catenin activity?
Based on the research paper, what is the relationship between YAP/TAZ and beta-catenin activity?
What is the proposed function of cytoplasmic YAP/TAZ in cells that are not under Wnt stimulation?
What is the proposed function of cytoplasmic YAP/TAZ in cells that are not under Wnt stimulation?
According to current understanding, how does Wnt stimulation affect cytoplasmic YAP/TAZ?
According to current understanding, how does Wnt stimulation affect cytoplasmic YAP/TAZ?
Which method was employed to detect the proteins associated with Axin1 in Wnt OFF cells?
Which method was employed to detect the proteins associated with Axin1 in Wnt OFF cells?
In the absence of Axin, what is the localization pattern of YAP/TAZ?
In the absence of Axin, what is the localization pattern of YAP/TAZ?
What role do YAP and TAZ play in the context of tissue regeneration?
What role do YAP and TAZ play in the context of tissue regeneration?
According to Figure 2F, how does the addition of Wnt3A impact the relationship between Axin1 and YAP/TAZ over time?
According to Figure 2F, how does the addition of Wnt3A impact the relationship between Axin1 and YAP/TAZ over time?
In the experiment relating to the intestine, in which specific region are both YAP and TAZ proteins expressed in dissected tissue?
In the experiment relating to the intestine, in which specific region are both YAP and TAZ proteins expressed in dissected tissue?
After intestinal-specific knockout of APC in mice, what happens to YAP and TAZ proteins in villi, according to Figure 3A?
After intestinal-specific knockout of APC in mice, what happens to YAP and TAZ proteins in villi, according to Figure 3A?
When control Villin-CreERT2 mice or those carrying double YAP/TAZ conditional alleles are used to explant Crypt tissue, what happens next?
When control Villin-CreERT2 mice or those carrying double YAP/TAZ conditional alleles are used to explant Crypt tissue, what happens next?
What processes does YAP/TAZ control, after the Tamoxifen-mediated combined deletion?
What processes does YAP/TAZ control, after the Tamoxifen-mediated combined deletion?
According to Figure 4, what is affected by the loss of YAP/TAZ in the Axin1 complex?
According to Figure 4, what is affected by the loss of YAP/TAZ in the Axin1 complex?
What happens during HEK293 transfection in association to TOP-FLASH, according to Figure 4?
What happens during HEK293 transfection in association to TOP-FLASH, according to Figure 4?
According to Figure 5, what can be said about YAP/TAZ and B-cantenin?
According to Figure 5, what can be said about YAP/TAZ and B-cantenin?
According to Figure 5, what do you need to do to perform an effective experiment in luciferase with the TOP-FLASH reporter in HEK293 cells?
According to Figure 5, what do you need to do to perform an effective experiment in luciferase with the TOP-FLASH reporter in HEK293 cells?
According to Figure 6, what is used to propagate Stem Cells?
According to Figure 6, what is used to propagate Stem Cells?
According to Figure 6, knocking out what is equivalent to having CH present for stem cells?
According to Figure 6, knocking out what is equivalent to having CH present for stem cells?
For stem cells, what can now be maintained by only doing only one direct experiment?
For stem cells, what can now be maintained by only doing only one direct experiment?
According to Figure 6, when discussing b-cantenin on TCF, what is also required at the same time?
According to Figure 6, when discussing b-cantenin on TCF, what is also required at the same time?
After reviewing the content, which of the methods would help to show that components are integral to the b-cantenin destruction complex?
After reviewing the content, which of the methods would help to show that components are integral to the b-cantenin destruction complex?
According to the content here, which of the following options can the Azzolin method show to be the double role of YAP and TAZ?
According to the content here, which of the following options can the Azzolin method show to be the double role of YAP and TAZ?
Flashcards
Wnt signaling pathway
Wnt signaling pathway
A signaling cascade involved in development and cancer, initiated by Wnt ligands binding to Frizzled receptors.
Wnt proteins
Wnt proteins
Secreted lipid-modified glycoproteins that act as ligands in the Wnt signaling pathway.
Frizzled family (GPCRs)
Frizzled family (GPCRs)
Receptors on the cell surface that bind Wnt proteins, initiating the Wnt signaling cascade.
β-catenin
β-catenin
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Destruction complex
Destruction complex
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GSK3β
GSK3β
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TCF
TCF
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Wnt proteins
Wnt proteins
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GSK3β differential phosphorylation
GSK3β differential phosphorylation
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Porcupine (Porc)
Porcupine (Porc)
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Evi/Wntless
Evi/Wntless
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Proteosome degradation
Proteosome degradation
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vATPase
vATPase
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beta-catenin
beta-catenin
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YAP and TAZ
YAP and TAZ
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Kinases
Kinases
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Multivesicular bodies (MVBs)
Multivesicular bodies (MVBs)
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APC function
APC function
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Wnt growth factors
Wnt growth factors
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Study Notes
Wnt Signaling Pathway Discovery
- Wnt signaling was discovered through oncogenic retrovirus research
- In 1982, Roel Nusse and Harold Varmus identified a new mouse proto-oncogene called int1, or integration 1
- Int1 was later characterized as a Wnt or Wingless-related integration 1 signaling molecule during studies of a mouse mammary tumor virus
Wnt Function and Characteristics
- Wnt regulates segment polarity during embryonic development, influencing body axis formation and lateral symmetry
- Wnt proteins are secreted lipid-modified glycoproteins that undergo palmitoylation and glycosylation to ensure proper secretion
- Wnt proteins act as ligands to activate different Wnt pathways in paracrine and autocrine manners
Wnt Genes and Signaling
- Most mammalian genomes, including the human genome, contain 19 Wnt genes categorized into 12 conserved Wnt subfamilies
- Wnt signaling can be canonical or non-canonical
- Different co-receptors and Wnt signaling molecule isoforms determine the specific type of signaling
Wnt Signaling Components
- Wnt proteins bind to Frizzled family receptors which are GPCRs on the cell surface
- The signal transduction involves several cytoplasmic relay components, including GSK3β differential phosphorylation
- Beta-catenin is transduced and enters the nucleus to form a complex with TCF, which activates the transcription of Wnt target genes
Degradation Regulation
- Proteosome degradation impacts Wnt activation and signaling
YAP/TAZ in Wnt Signaling: Overview
- This study focuses on the interplay between Wnt and Hippo signaling via Hippo signal transducer proteins Yap and Taz
- YAP/TAZ and Wnt/β-catenin do not operate independently and are hypothesized to influence each other
- Phosphorylated β-catenin encourages TAZ degradation by acting as a presenting factor for TAZ to b-TrCP, or ubiquitin ligase
Hypothesis on Cytoplasmic YAP/TAZ
- Cytoplasmic YAP/TAZ are proposed as integral factors within the destruction complex
- Cells lacking Wnt would sequester YAP/TAZ within the destruction complex to degrade β-catenin
- Wnt stimulation eliminates or inhibits cytoplasmic YAP/TAZ, resulting in β-catenin stabilization and YAP/TAZ nuclear accumulation
Immunoprecipitation (IP) in Protein-Protein Interactions
- Immunoprecipitation was employed to determine protein-protein interactions
- Protein composition in Wnt OFF cells was identified through immunoprecipitations for endogenous Axin1
- Proteins that associate are detected using western blotting
Axin1 Binding and Data Support
- Axin1 binds established elements of the destruction complex and also strongly binds to endogenous YAP and TAZ
- In Wnt OFF conditions, YAP/TAZ associates with the destruction complex through interaction with Axin
- YAP/TAZ localizes to the nucleus when Axin is absent
Purified Wnt3A Ligand Effect
- The effect of purified Wnt3A ligand was monitored on the subcellular localization of endogenous YAP by immunofluorescence in various cell types
- YAP was primarily cytoplasmic in confluent, untreated cells but relocalized markedly to the nucleus following Wnt treatment
Consequences of Wnt-Induced YAP/TAZ
- Wnt induced YAP/TAZ nuclear localization connects with transcriptional activation of the synthetic TEAD reporter or 8xGTIIC-Lux
- Paralleled also with direct YAP/TAZ target genes Cyr61 and Ankrd1 are activated
- YAP/TAZ nuclear accumulation and TEAD reporter activation were detected as early as 30 minutes post-Wnt stimulation
- This timing is comparable to initial detection of the TCF/b-catenin reporter TOP-FLASH
Wnt Stimulation and Molecular Changes
- Wnt stimulation alters the complex's composition relative to YAP/TAZ such that their association with Axin1 rapidly decreases
- Association with Axin1 becomes undetectable after 30 minutes for TAZ and 2 hours for YAP following Wnt3A addition
Wnt-ON cells and LRP6 function
- LRP6 releases YAP/TAZ from the destruction complex by displacing them from Axin1
- Figures H-J validates raising the doses of LRP6 to titrate Axin1 away from interacting with YAP/TAZ
Intestinal Study and Tissue Homeostasis
- Intestinal epithelium serves as a model for Wnt-driven tissue homeostasis and regeneration
- Wnt signaling is active in crypt cells,devoted to intestinal tissue replenishment, but inactive in villi, also important for epithelial repair
- Both YAP and TAZ show specific expression in the crypt compartment
Additional YAP/TAZ Insights
- YAP/TAZ nuclear localization in crypt cells is consistent with regulation by endogenous Wnt signals
- YAP and TAZ proteins become ectopically stabilized in villi after intestinal-specific knockout of APC
APC and Mutant Analysis
- APC, or adenomatous polyposis coli, functions as an intestinal tumor suppressor and is part of the destruction complex
- Adult mice, injected with tamoxifen and sacrificed after 3 days, time point when Villin-CreERT2;Apcfl/fl mice became moribund
- Triple mutant mice showed with no signs of aberrant crypt hyperplasia after 3 weeks
- This was the set end-point for observation of tumors/cancers
Crypt Study and Mutations
- Crypt mutations were examined in an organoid model, a system requiring Wnt signaling and is reminiscent of in vivo regeneration
- Crypts were explanted from control Villin-CreERT2 mice or from mice carrying double YAP/TAZ conditional alleles
- Crypts were then seeded in Matrigel with Wnt-agonist R-Spondin which is essential for crypt maintenance and growth in 3-D culture, also known as organoid
YAP/TAZ Results
- Tamoxifen deletion of YAP/TAZ blocked crypt growth
- Led to the demise of the mutant crypts, to demonstrate the role of YAP/TAZ in these processes
YAP/TAZ with Wnt
- Lack of YAP can lead to greater amounts of beta-TrCP in the destruction complex
- There is reporter expression, controlled by β-catenin/TCF and shows that YAP/TAZ influence levels of nuclear β-catenin
HEK293 Cell Study on Effects
- In Lane 1: YAP/TAZ depletion activates TOP-FLASH reporter, a wnt signaling
- In Lane 2: knocking down endogenous β-catenin gets rid of the effects of YAP/TAZ Depletion
- In Lanes 3 and 4: cells had β-catenin siRNA and reconstituted with either wild-type or phosphomutant siRNA-insensitive β-catenin
- There seems to be a greater basal activity that is is not further increased after YAP/TAZ Knockdown
Wnt3A effects
- Interactions with Axin1 will happen after Wnt3A stimulation
ES Cell Info and Goals
- With mouse embryonic stem cells as these can be propagated in an undifferentiated and pluripotent state
- When cultured with two MEK and GSK3 inhibitors, with transcriptional responses for cell maintenance and genetic ablation
Model Insights
- The work demonstrates the integration of YAP and TAZ into the β-catenin destruction complex
- Contributes insights in cell reprogamming with Wnt Singaling
Azzolin Model
- Demonstrates a double role for YAP/TAZ.
- In the absence of Wnt ligands, YAP/TAZ become complex and recruit β-TrCP in order to regulate Wnt singaling
- In an activated pathway, YAP/TAZ and bound B-TCrP shift from Axin 1 because LRP sequesters the distruction complex
- Free YAP/TAZ is a factor that effects Wnt Signials, showing Hippo and Wnts strong connection.
Wnt and Impact to Cancer
- Has a huge impact on carcinogenesis regarding colorectal cancer, very well understood
- Loss of APC is also understood in colorectal cancer
- Genome editing via editing shows CRC can be solved without going the traditional pathway.
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