(4.3) ABNORMAL PROTEINS AND PROTEIN AGGREGATION
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Questions and Answers

What is a common consequence of misfolded proteins in biological systems?

  • Deterioration of cellular environments. (correct)
  • Increased protein synthesis.
  • Enhanced enzyme activity.
  • Improved protein interactions.

Which factor is most likely to lead to the necessity for molecular chaperones?

  • Complex or large proteins with kinetic interference. (correct)
  • Sporadic genes expression levels.
  • The presence of small, non-functional peptides.
  • Reduced amino acid availability.

How do molecular chaperones assist in protein folding?

  • By preventing protein degradation.
  • By providing an environment for proper conformation. (correct)
  • By increasing the rate of protein synthesis.
  • By promoting spontaneous folding.

What is a potential result when there is dysfunction in a molecular chaperone?

<p>Increased aggregation of proteins. (D)</p> Signup and view all the answers

Which of the following best describes a prion-related disease mechanism?

<p>Misfolded prions induce misfolding in normal proteins. (B)</p> Signup and view all the answers

What role do chaperones play in protein folding?

<p>They assist in correct folding of proteins. (A)</p> Signup and view all the answers

What can result from protein aggregation?

<p>Clogging processes and misfolding of other proteins. (C)</p> Signup and view all the answers

What is a consequence of prion misfolding?

<p>They induce misfolding in other proteins. (B)</p> Signup and view all the answers

Which of the following accurately describes a fibril?

<p>An aggregate form of misfolded proteins. (D)</p> Signup and view all the answers

How can aging influence protein aggregation?

<p>It increases the expected accumulation of misfolded proteins. (B)</p> Signup and view all the answers

What is the result of the overexpression of certain proteins?

<p>Inappropriate protein interactions and potential aggregation. (B)</p> Signup and view all the answers

What characterizes transmissible spongiform encephalopathies?

<p>They are caused by infectious misfolded proteins. (A)</p> Signup and view all the answers

What is a characteristic of sporadic spongiform encephalopathies?

<p>They usually have a mean survival of less than six months. (C)</p> Signup and view all the answers

Which post-translational modification is indicated as influencing the activity of proteins like RELA?

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

What is the main cause of misfolding in proteins, as discussed in the context of ALS and Alzheimer's disease?

<p>Infectious-like behavior of misfolded proteins (C)</p> Signup and view all the answers

Which of the following statements about genetic spongiform encephalopathies is true?

<p>They follow a familial pattern and progress over a lifetime. (D)</p> Signup and view all the answers

Which of the following best describes the role of protein modifications in biochemical pathways?

<p>They can create a complex array of proteins with different functions. (D)</p> Signup and view all the answers

What common feature is shared by prion diseases?

<p>They lead to rapid neurodegeneration. (C)</p> Signup and view all the answers

How do post-translational modifications like methylation and phosphorylation interact in terms of protein function?

<p>They can impact protein activity in a collaborative manner. (D)</p> Signup and view all the answers

What percentage of spongiform encephalopathy cases are attributed to acquired factors?

<p>Less than 1% (C)</p> Signup and view all the answers

What is one primary consequence of protein misfolding related to infectious-like behavior?

<p>Induction of additional misfolding in other proteins (B)</p> Signup and view all the answers

Which process is essential for creating a functional protein from a string of amino acids?

<p>Post-translational modification (B)</p> Signup and view all the answers

What type of proteins are typically unable to achieve their native conformations and can lead to aggregation?

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

How are prokaryotic protein aggregates predominantly characterized?

<p>By altered growth rates (B)</p> Signup and view all the answers

What are prions primarily classified as?

<p>Small infectious protein particles (A)</p> Signup and view all the answers

Which disease is associated with proteins that exhibit prion-like behavior?

<p>Amyotrophic Lateral Sclerosis (ALS) (A)</p> Signup and view all the answers

Which of the following best describes the most common form of prion disease?

<p>Sporadic prion disease (D)</p> Signup and view all the answers

In the context of protein structure, what outcome occurs when a protein cannot fold properly?

<p>It remains in its primary structure. (B)</p> Signup and view all the answers

What is a significant clinical implication of protein aggregation in neurodegenerative diseases?

<p>It contributes to neuron degeneration. (D)</p> Signup and view all the answers

What percentage of prion disease cases are typically considered sporadic?

<p>80-95% (A)</p> Signup and view all the answers

Which of the following modifications can contribute to making proteins active?

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

What mechanism is primarily associated with prion-like infectious behavior in misfolded proteins?

<p>Aggregation that leads to disease (A)</p> Signup and view all the answers

What is the primary role of molecular chaperones in protein folding?

<p>To assist in achieving native folds of proteins (D)</p> Signup and view all the answers

Which of the following post-translational modifications is primarily involved in adding hydroxyl groups to proteins?

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

What consequence can result from protein aggregation related to cellular function?

<p>Impairment of cellular processes and potential disease (B)</p> Signup and view all the answers

In the context of prion diseases, what is a key feature that differentiates prions from other proteins?

<p>Prions can induce misfolding in normal proteins. (C)</p> Signup and view all the answers

Which type of post-translational modification can either activate or inactivate protein function?

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

What is the relationship between protein misfolding and the function of molecular chaperones?

<p>Chaperones help prevent misfolding during protein synthesis. (B)</p> Signup and view all the answers

What type of post-translational modification involves the addition of sugar molecules?

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

How can disruption of molecular chaperones contribute to disease?

<p>By leading to increased protein misfolding (A)</p> Signup and view all the answers

Which post-translational modification can lead to the degradation of proteins?

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

Flashcards

Protein Aggregation

The clustering of misfolded proteins into large clumps.

Misfolded Proteins

Proteins that have incorrect 3-D shapes.

Creon Stage

When misfolded proteins cause more misfolding.

Prion

A misfolded protein that can cause other proteins to misfold.

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Fibril

A type of protein aggregate.

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Transmissible Spongiform Encephalopathies

Brain diseases caused by prions.

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Protein Chaperones

Proteins that assist in proper protein folding.

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Protein Folding

The process of a protein adopting its 3-D functional structure.

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Aggregation Problems

Toxicity, propagation of misfolded proteins and resulting illnesses are direct consequences of protein aggregation (e.g., prion diseases).

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Cellular Function

The normal activities of a cell.

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Neurodegenerative Diseases

Diseases that involve the deterioration of neurons in the brain.

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Misfolding Proteins

A process where proteins fold incorrectly, leading to other proteins misfolding, potentially causing diseases.

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Spongiform Encephalopathies

A group of rare progressive neurodegenerative diseases characterized by spongy holes in the brain tissue.

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Sporadic Spongiform Encephalopathy

The most common type of spongiform encephalopathy, often with a rapid progression, less than 6 months, and includes diseases like Creutzfeldt-Jakob disease.

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Genetic Spongiform Encephalopathy

A type of spongiform encephalopathy linked to a genetic mutation in proteins, leading to progressive disease over a lifetime.

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Acquired Spongiform Encephalopathy

A rare type of spongiform encephalopathy that arises from external sources, often less than 1 percent of cases.

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Protein Misfolding

The incorrect folding of proteins that may contribute to diseases like ALS and Alzheimer's.

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Protein Modifications

Altering a protein's structure or function by adding chemical groups, like methylation or phosphorylation, to amino acids.

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Biochemical Pathways

Steps in which molecules are progressively changed and modified to perform a specific cellular function.

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RELA Modification

Changes in the RELA protein alter its ability to influence transcription; modifications can either activate or suppress its activity.

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Methylation

Adding a methyl group to a molecule, often affecting its activity.

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Phosphorylation

Adding a phosphate group to a molecule, often affecting its activity.

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Spontaneous Protein Folding

A consistent process where a protein naturally assumes its functional 3D structure (tertiary structure), driven by hydrophobic interactions, hydrogen bonding, and other non-covalent forces.

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Non-spontaneous Protein Folding

Protein folding that requires intermediate steps due to kinetic interference. This is common in large or complex proteins where there are barriers to achieving the final 3D structure.

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Kinetic Interference

Obstacles or barriers that prevent a protein from folding into its functional conformation, often related to the large size or complex interactions within the protein structure.

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Misfolded Protein

A protein that doesn't fold correctly into its native structure, forming a non-native conformation.

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Molecular Chaperones

Proteins that assist other proteins in folding correctly. They help prevent misfolding and aggregation.

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Protein Aggregation

The clumping together of misfolded proteins, potentially forming harmful deposits.

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ALS (Amyotrophic Lateral Sclerosis)

A disease linked to misfolded proteins (potentially caused by dysfunctional chaperones) leading to progressive neurological damage.

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Tertiary Structure

The 3D arrangement of a polypeptide chain, crucial for a protein's function. It results from various interactions among amino acid side chains.

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Misfolded proteins

Proteins with incorrect 3-D shapes that can clump together.

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Protein aggregation

The clumping together of misfolded proteins.

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Prions

Infectious protein particles that cause other proteins to misfold.

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Prion diseases

Diseases caused by prions, involving misfolded proteins and brain damage.

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Spongiform encephalopathies

Brain diseases characterized by holes in brain tissue, caused by prions.

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Sporadic diseases

Occurring randomly/without a clear reason with an average survival time below 6 months

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Genetic diseases

Prion diseases attributed to a genetic cause.

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Acquired diseases

Infection-based cause related to the transmission of prions

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ALS(Amyotrophic Lateral Sclerosis)

Neurological disease related to prion-like behaviour of SOD1 (superoxide dismutase).

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Protein modifications

Chemical changes to a protein, influencing its structure and function.

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Protein structure and function link

Specific protein structures determine specific protein functions including levels of protein structure.

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Post-translational Modification

Any change to a protein after it's made (translated).

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Protein Aggregation

Misfolded proteins clump together.

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Molecular Chaperone

Protein helpers for correct folding.

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Phosphorylation

Adding a phosphate group to a protein.

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Hydroxylation

Adding a hydroxyl group.

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Protein Folding

How proteins take their 3D shape for function.

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Tertiary Structure

The complex 3D shape of a protein.

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Protein Function

What a protein does in the cell.

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Prion

Misfolded protein causing more misfolding.

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Kinase

Adds phosphates to proteins.

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Phosphate

A chemical group important in cellular regulation.

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Disulfide Bond

A chemical bond between 2 cysteine or sulfur atoms.

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Spontaneous Folding

Proteins that fold into their 3-D shape without help.

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Study Notes

Protein Modifications

  • Proteins are regulated by modifications, including transcription, translation, and post-translational modifications.
  • Post-translational modifications include addition or removal of functional groups (e.g., phosphorylation, hydroxylation, sulfation, acetylation, lipidation, methylation, glycosylation, ubiquitylation).
  • Phosphorylation is a common, reversible modification, with kinases adding phosphate groups and phosphatases removing them.
  • Protein function depends on proper folding.
  • Modifications can affect protein folding, and misfolding can lead to aggregation and disease.

Protein Folding

  • Folding can be spontaneous or require molecular chaperones.
  • Molecular chaperones assist folding, ensuring proteins acquire correct 3D structures.
  • Domains and regions within proteins interact, enabling folding.
  • Kinetic interference can hinder or slow down spontaneous folding.
  • Misfolded proteins can aggregate, forming aggregates or fibrils.

Protein Aggregation

  • Protein aggregation is the accumulation of misfolded proteins.
  • Aggregates can clog processes, interfere with transport, and contribute to diseases (Creutzfeldt-Jakob disease, Alzheimer's etc).
  • Misfolded protein can cause further misfolding (prions).
  • Chaperones prevent protein aggregation.
  • Improper folding can lead to toxic buildup.

Spongiform Encephalopathies

  • Spongiform encephalopathies are caused by misfolded proteins forming aggregates and fibrils.
  • Types include sporadic, genetic, and acquired.
  • These diseases have progressive symptoms that are often fatal, with a short life expectancy (e.g., less than six months).
  • Modifcations are crucial components in protein function.

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Related Documents

Protein Modifications and Folding PDF
Abnormal Proteins and Protein Aggregation BMS 532 Lecture Notes PDF

Description

Explore the intricate processes of protein modifications and folding in this quiz. Understand the significance of post-translational modifications such as phosphorylation and the role of molecular chaperones. Learn how these processes impact protein functionality and relate to diseases caused by misfolding and aggregation.

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