retinoblastoma protein

Examples of retinoblastoma protein in the following topics:

• Regulator Molecules of the Cell Cycle

  • Phosphorylation activates the protein by changing its shape.
  • The best understood negative regulatory molecules are retinoblastoma protein (Rb), p53, and p21.
  • Retinoblastoma proteins are a group of tumor-suppressor proteins common in many cells.
  • The concentrations of cyclin proteins change throughout the cell cycle.
  • Cyclin-dependent kinases (Cdks) are protein kinases that, when fully activated, can phosphorylate and activate other proteins that advance the cell cycle past a checkpoint.

• Biochemical Products of Recombinant DNA Technology

  • Recombinant DNA technology engineers microbial cells for producing foreign proteins, and its success solely depends on the precise reading of equivalent genes made with the help of bacterial cell machinery.
  • Isolating proteins in large quantities: many recombinant products are now available, including follicle stimulating hormone (FSH), Follistim AQ vial, growth hormone, insulin and some other proteins.
  • Making possible mutation identification: due to this technology, people can be easily tested for mutated protein presence that can lead to breast cancer, neurofibromatosis, and retinoblastoma.

• Plant DNA Viruses

  • Like many viruses, geminivirus genomes encode only a few proteins, and are therefore dependent on host cell factors for replication.
  • The segments each encode a single protein.
  • Each member has up to 4 segments encoding replication proteins of ~33 kDa.
  • The other segments encode products of 10-20 kDa in size and include a coat protein of ~19 kDa and a protein with a retinoblastoma binding motif.
  • These viruses (family Phycodnaviridae) are huge dsDNA viruses with genomes ranging from 160 to 560 kb with up to 600 protein-encoding genes, making them distinctly different from viruses infecting higher plants.

• Mapping Protein-Protein Interactions

  • Mapping protein-protein interactions gives us a better understanding of molecular mechanisms inside the cell.
  • The protein complexes formed could be stable (proteins interact for a prolonged period of time) or transient (proteins interact for a brief period of time).
  • The tag serves as a tool to purify the bait protein and associated proteins by affinity chromatography.
  • The identity of the protein associated with a given bait protein is determined by comparing its peptide fingerprint against available databases.
  • Principle of the bait and prey method for the study of protein-protein interaction.

• Regulating Protein Activity and Longevity

  • The addition of a phosphate group to a protein can result in either activation or deactivation; it is protein dependent.
  • The addition of methyl groups to a protein can result in protein-protein interactions that allows for transcriptional regulation, response to stress, protein repair, nuclear transport, and even differentiation processes.
  • Methylation in the proteins negates the negative charge on it and increases the hydrophobicity of the protein.
  • The addition of an ubiquitin group to a protein marks that protein for degradation.
  • These proteins are moved to the proteasome, an organelle that functions to remove proteins to be degraded .

• Denaturation and Protein Folding

  • This shape determines the protein's function, from digesting protein in the stomach to carrying oxygen in the blood.
  • If the protein is subject to changes in temperature, pH, or exposure to chemicals, the internal interactions between the protein's amino acids can be altered, which in turn may alter the shape of the protein.
  • Although the amino acid sequence (also known as the protein's primary structure) does not change, the protein's shape may change so much that it becomes dysfunctional, in which case the protein is considered denatured.
  • Chaperone proteins (or chaperonins) are helper proteins that provide favorable conditions for protein folding to take place.
  • (Top) The protein albumin in raw and cooked egg white.

• Proteolytic Degradation

  • The mechanisms of proteolytic degradation are necessary for obtaining amino acids via degradation of digested proteins, preventing accumulation or abnormal concentrations of proteins, and by regulating cellular processes by removing proteins no longer needed.
  • Proteasomes are protein complexes that function in the degradation of unneeded or damaged proteins via proteolysis.
  • The recognition of this ubiquitin signal by the proteasome results in degradation of the protein into its amino acids, which are then recycled and reused for the synthesis of new proteins.
  • The lysosome contains proteases that are able to target and degrade proteins.
  • Once the protein arrives at the proteasome, the protein is degraded into its amino acids which are then reused for synthesis of new proteins.

• Proteomics

  • The proteome is the entire complement of proteins, including the modifications made to a particular set of proteins, produced by an organism or system.
  • Fourth, many proteins form complexes with other proteins or RNA molecules.
  • Finally, protein degradation rate plays an important role in protein content.
  • Most proteins function in collaboration with other proteins.
  • Several methods are available to probe protein–protein interactions.

• Protein Folding, Modification, and Targeting

  • The native conformation of a protein is a stable three-dimensional structure that strongly determines a protein's biological function.
  • When a protein loses its biological function as a result of a loss of three-dimensional structure, we say that the protein has undergone denaturation.
  • The denatured state of the protein does not equate with the unfolding of the protein and randomization of conformation.
  • These sequences at the amino end or the carboxyl end of the protein can be thought of as the protein's "train ticket" to its ultimate destination.
  • This protein serves as a channel for chloride ions.

• Facilitated transport

  • In both cases, they are transmembrane proteins.
  • Another type of protein embedded in the plasma membrane is a carrier protein.
  • Carrier proteins are typically specific for a single substance.
  • Each carrier protein is specific to one substance, and there are a finite number of these proteins in any membrane.
  • Channel proteins transport much more quickly than do carrier proteins.