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Protein Phosphorylation 1
Biomolecules
University of Lincoln
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Protein phosphorylation 1
● Protein phosphorylation ○ Post-translational modification - after proteins is synthesised ○ Enzyme mediated ○ ~ 30% eukaryotic proteins are phosphorylated - important as regulation is dependent on phosphorylation ○ Effective way in which to regulate proteins ○ Can be reciprocal to glycosylation - substantial degree of regulation
● Phosphoprotein states ○ A transfer of phosphoryl groups from a gene or a protein ■ E. transfer of ATP to ADP - one phosphate group which isnt phosphorylated onto a protein that is phosphorylated ○ Protein phosphorylation depends on enzymes ■ Kinases - enzymes that transfer phosphate groups to enzymes ■ Phosphatases - remove phosphate groups from enzymes ○ And ATP - a phosphoryl donor
● Phosphoamino acids
● Why is phosphorylation so effective? ○ A phosphoryl group adds two negative charges to the protein ■ Adds two negative charges to the protein ○ A phosphoryl group can form 3 or more hydrogen bonds ■ Can form intramolecular interactions - changing the structure of the protein so it needs to be regulated ○ Phosphorylation and dephosphorylation tightly regulated ○ Can have global effect on protein
● Conformational changes
● Phosphoswitch - active and inactive forms ○ Proteins that due to phosphorylation can form two different shapes ■ Closed inactive state ■ Open active state ○ Grey molecules - open conformation of phosphoswitch
● Linear ○ Transfers one phosphate group from one position to another to another ○ In important pathways, e. cell death, there needs to be lots of checkpoints to make sure it is ‘ready’ to ‘die’ ● Cascades ○ One phosphorylation event leading to transfer phosphate event in many cases ○ Multiplying multiple times to the kinases that have a broader function ○ Typically may happen when exposed to a new environment, e. exposed to a new hormone
● Proliferation, cell division + differentiation - if it doesn’t occur then it can cause cancer
● Glycosylation/phosphorylation dynamics
○ Phosphorylation and glycosylation are not (necessarily) mutually exclusive
● Phosphorylation and glycosylation are not necessarily mutually exclusive
● Reciprocal glycosylation/phosphorylation ○ Certain proteins can be O-glycosylated or phosporylated at same site ■ E. c-Myc
● Glycogen degradation
● Phosphorylation b - not phosphorylated - less active form
● Ser14 side chain is catalysed by phosphorylase b kinase
● Hormone stimulation ○ Stress causes release of acetylcholine ○ Increased acetylcholine leads to increased epinephrine ○ Epinephrine bound by receptor in liver or muscle ○ Signalling cascade activated
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● Summary ○ Described phosphorylation ■ Methodology of phosphorylation ○ Importance of phosphorylation on signalling ○ Examples of phosphorylation on action ■ Glycogen processing
Protein Phosphorylation 1
Module: Biomolecules
University: University of Lincoln
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- More from:BiomoleculesUniversity of Lincoln33 Documents
