RE - The Proteome Flashcards
What are the meanings of Genome, Transcriptome and Proteomes?
Genome
- Complete set of genes
Transcriptome
- Complete set of mRNA transcripts
Proteome
- Complete set of proteins expressed in system
What is meant by ‘Proteomics’? (2)
- Qualitative and quantitative studies of protein expression and function
- Refers to the techniques used to study the proteome
What is the importance of proteomics? (4)
Need proteomics because:
- Protein function dependent on structure, modifications and interactions – NOT predictable form primary sequence
- Abundance of mRNA may not reflect level or activity of corresponding proteins
- Protein function may depend on location with in the cell
- One to many relationship between genes and polypeptides/proteins
What are 3 complexities of the proteome and challenges for proteomics?
- Vast number of diverse types of proteins
- Proteomes are cell- and tissue-specific, and highly responsive to change
- Proteomes include very high and very low abundance proteins
What are 3 different levels of regulation?
- Transcriptional (e.g. alternative splicing)
- Translational regulation (e.g. alternative initiation)
- Post-translational modification (e.g. phosphorylation)
What are the main types of post-translational modifications?
- Acetylation (Lys)
- Ubiquitylation (Lys)
- Phosphorylation (Ser, Thr)
Alter protein function and localization
What is the significance of PTMs on a single protein? (3)
p53 protein is important tumor suppressor (inactivating mutations in >50% of cancers)
p53 extensively modified
- Phosphorylation
- Acetylation
Modifications regulate activity
How do combinations of PTMs influence proteome complexity?
Combinations of PTMs increase proteome complexity
What are 5 features of protein families?
- Sets of proteins that are related by protein sequence
- May have same domains and perform similar functions
- Arise due to gene duplication events through evolution
- Most proteins assigned to family with > 1 member
- Analysis of the proteome is complicated by protein families
What organisms are examples of same genome. different proteomes?
Ceterpillars and Butterfly
What are some classes of highly abundant proteins (4) and low abundant proteins (2)?
Most abundant proteins
- Metabolic enzymes
- Ribosomal proteins
- Structural proteins
- Heat-shock proteins
Least abundant
- Signaling proteins
- Transcription factor proteins
Descrive the protein expression levels in plasma (2)
- Blood plasma liquid part of blood (minus cells)
- Plasma extremely diverse proteome (bathes all cells in body)
