Hedgehog Signaling and Ptch1 Role

<p>Morphogenetic and developmental pathways. (D)</p> Signup and view all the answers

<p>p &lt; 0.01 and |log2FoldChange| &gt; 1. (D)</p> Signup and view all the answers

<p>36 to 50 KDa (C)</p> Signup and view all the answers

<p>Phosphorylation (D)</p> Signup and view all the answers

<p>Activation of the morphogenetic signal (B)</p> Signup and view all the answers

<p>Vesicular transport (A)</p> Signup and view all the answers

<p>Presence of at least one invariant cysteine (C)</p> Signup and view all the answers

<p>Facilitation of antero-posterior axis formation (A)</p> Signup and view all the answers

<p>19 (C)</p> Signup and view all the answers

<p>Facilitated diffusion (D)</p> Signup and view all the answers

<p>Promotes apoptosis in adult tissues (C)</p> Signup and view all the answers

<p>Regulating gene expression for body segmentation (C)</p> Signup and view all the answers

<p>SHH (B)</p> Signup and view all the answers

<p>Four (A)</p> Signup and view all the answers

<p>Proteasomal degradation (D)</p> Signup and view all the answers

<p>Cell cycle arrest (A)</p> Signup and view all the answers

<p>Translation of a 45 kDa precursor (D)</p> Signup and view all the answers

<p>Drosophila melanogaster (B)</p> Signup and view all the answers

<p>Increased cellular proliferation and tumor growth (B)</p> Signup and view all the answers

<p>Type II (D)</p> Signup and view all the answers

<p>Ligand dependent and paracrine activation (A)</p> Signup and view all the answers

<p>Aberrant activation in stem cells, either autocrine or paracrine (C)</p> Signup and view all the answers

<p>Type I (B)</p> Signup and view all the answers

<p>The PTCH protein has altered functionality. (D)</p> Signup and view all the answers

<p>It is a proto-oncogene. (D)</p> Signup and view all the answers

<p>Complete functional capacity at 100%. (D)</p> Signup and view all the answers

<p>No functional PTCH protein is present. (C)</p> Signup and view all the answers

<p>It serves as a tumor suppressor. (C)</p> Signup and view all the answers

<p>Complete loss of PTCH function leading to cancer. (C)</p> Signup and view all the answers

<p>Increased risk of cancer development. (B)</p> Signup and view all the answers

<p>To contribute to oncogenesis depending on whether genes act as suppressors or activators. (C)</p> Signup and view all the answers

<p>It shows complete loss of functional activity. (A)</p> Signup and view all the answers

<p>They will have a significantly lower tumor suppressor capacity. (A)</p> Signup and view all the answers

<p>Guides cell differentiation and tissue patterning (B)</p> Signup and view all the answers

<p>Ptch1 represses SMO activity and inhibits GLI activation (A)</p> Signup and view all the answers

<p>It introduces a beta-galactosidase reporter gene in place of part of the coding sequence (D)</p> Signup and view all the answers

<p>GLI proteins are ubiquitinated and degraded (D)</p> Signup and view all the answers

<p>By post-natal day 60 (B)</p> Signup and view all the answers

<p>Histochemical staining for beta-galactosidase activity (C)</p> Signup and view all the answers

<p>It is upregulated in the presence of Shh signaling (D)</p> Signup and view all the answers

<p>They guide cells to their appropriate locations in embryonic development (C)</p> Signup and view all the answers

<p>It promotes the transcription of target genes involved in development (A)</p> Signup and view all the answers

A multi-protein complex assembled at the cell membrane that receives and transmits Wnt signals, initiating downstream signal transduction, promoting cell growth, and influencing tissue patterning.

A family of secreted signaling molecules crucial for embryonic development, cell fate determination, and tissue homeostasis.

A protein involved in the Wnt signaling pathway that plays a crucial role in transducing the signal from the cell surface to the nucleus, ultimately impacting gene expression.

Essential for Wnt protein trafficking and secretion, acting as a molecular chaperone to guide Wnt proteins out of the cell to reach their target cells.

A mechanism of Wnt transport involving thin, elongated cellular projections called cytonemes, providing a direct route for long-distance Wnt communication between cells.

The movement of molecules through a membrane or within a cell, driven by the concentration gradient, from areas of higher concentration to lower concentration, without requiring energy.

A group of secreted factors that inhibit Wnt signaling, acting as brakes to regulate Wnt activity and prevent uncontrolled growth or developmental abnormalities.

A developmental process where the symmetrical structure of an embryo is broken down, leading to the establishment of distinct body axes and the formation of different tissues and organs.

The Hedgehog (HH) pathway is a fundamental signaling pathway initially discovered through studies of drosophila larvae.

The HH pathway plays a critical role in embryonic development, influencing processes like cell differentiation, body segmentation, and organ formation.

In adult organisms, the HH pathway regulates stem cell activity and homeostasis, ensuring proper tissue maintenance and regeneration.

Mammals have three homologous Hedgehog ligands: Desert Hedgehog, Indian Hedgehog, and the most studied, Sonic Hedgehog (SHH).

Hedgehog ligands are initially synthesized as 45 kDa precursors undergoing various post-translational modifications within the endoplasmic reticulum (ER) before secretion.

Hedgehog ligands are secreted through four distinct mechanisms, including direct secretion, formation of soluble oligomers, lipoprotein-mediated transport, and exovesicle release.

Direct secretion involves the Hedgehog ligand directly traversing the cell membrane with the aid of specific protein partners.

In soluble oligomer secretion, multiple Hedgehog ligands associate to form a complex that is released from the cell.

A protein that acts as a repressor of the Hedgehog (HH) signaling pathway. When Ptch1 is inhibited, the HH pathway is activated.

A protein involved in the HH pathway that is upregulated when Ptch1 is inhibited. It acts as a receptor for the HH signal.

The consequence of a conditional knockout of Ptch1 in astrocytes is an upregulation of the SHH pathway.

The HH pathway is involved in developmental processes such as morphogenesis. Disregulation of this pathway can lead to developmental abnormalities.

A genetic disorder caused by mutations in the PTCH1 gene, which leads to a hyperactivation of the HH signaling pathway.

A signaling pathway crucial for embryonic development, tissue patterning, and cell fate determination. It involves a cascade of events triggered by a family of secreted proteins called Hedgehog (Hh) molecules.

A protein that acts as a receptor for Hedgehog (Hh) ligands. It inhibits the activity of Smoothened (SMO) in the absence of Hh, preventing signal transduction.

A transmembrane protein that acts as a signal transducer in the Hedgehog (Hh) pathway. It becomes activated when Ptch1 is inhibited by Hedgehog binding, leading to downstream signaling.

A family of transcription factors that regulate gene expression in response to Hedgehog (Hh) signaling. They can act as activators or repressors, influencing cell fate and development.

A secreted protein that is a major morphogene involved in embryonic development. It acts as a ligand for the Hedgehog (Hh) pathway, binding to Ptch1 and initiating the signaling cascade.

A mechanism by which Shh signaling is regulated. In the absence of Shh, SMO is inhibited by Ptch1, leading to ubiquitinylation and degradation of GLI proteins, resulting in transcriptional repression.

A mechanism by which Shh signaling is activated. When Shh binds to Ptch1, SMO is activated, allowing GLI proteins to translocate to the nucleus and activate transcription.

The study of how the Hedgehog (Hh) pathway influences the development of the cerebral cortex, a part of the brain.

A genetic modification where the Ptch1 gene is replaced with a LacZ-neo fusion gene. This allows for the visualization of Ptch1 expression using Beta-galactosidase.

The process in which the density of cells in different layers of the cerebral cortex changes over time. This reflects the developmental progression of the brain.

The Hedgehog (HH) signaling pathway plays a crucial role in regulating cell growth and development. When this pathway malfunctions, it can lead to uncontrolled cell proliferation and the development of cancer.

Type I activation is independent of any ligand binding, suggesting an internal dysfunction within the pathway.

Type II activation involves the cancer cells producing their own Hedgehog ligand, creating a self-stimulating loop.

Type III activation relies on neighboring cells producing the Hedgehog ligand, signaling the cancer cells to grow.

Type IV activation occurs in stem cells, where the pathway can be activated through both autocrine and paracrine mechanisms, leading to uncontrolled proliferation and tumor formation.

In the HH pathway, a protein called Patched (PTCH) acts as a receptor, inhibiting the activity of another protein called Smoothened (SMO).

When a Hedgehog ligand binds to PTCH, it relieves the inhibition of SMO, allowing SMO to activate downstream signaling events. This leads to the expression of genes involved in developmental processes.

Mutations in the PTCH gene can lead to an overactive HH pathway, contributing to the development of cancers.

A tumor suppressor gene inhibits cell growth and prevents the formation of tumors.

A proto-oncogene can contribute to the development of cancer when it is mutated, leading to excessive cell growth or survival.

The HH pathway plays an important role in embryonic development, influencing processes like cell differentiation, body segmentation, and organ formation.

In adult organisms, the HH pathway regulates stem cell activity and homeostasis, ensuring proper tissue maintenance and regeneration.

The HH pathway is involved in various developmental and physiological processes, making it a crucial target for potential therapeutic interventions in various diseases.

The HH pathway is a complex signaling cascade that plays a critical role in regulating a wide range of biological processes. Understanding its intricacies is essential for developing effective strategies for disease prevention and treatment.