BS2092 Molecular Cell Biology: Cell Signalling KT2 - Phosphorylation in Signalling 1

This set of vocabulary flashcards covers the molecular mechanisms of protein phosphorylation, the structure and function of kinases, the role of receptor tyrosine kinases (RTKs) in cell signaling, and experimental methods used to detect phosphorylation events.

Phosphorylation

The transfer of a phosphoryl group from an $ATP$ donor to a hydroxyl group ($-OH$) on a substrate, such as carbohydrates, nucleic acids, proteins, or lipids.

Kinases

Enzymes that accelerate the transfer of a phosphoryl group from $ATP$ to a hydroxyl group on a substrate while providing substrate specificity.

Kinase Domains

Common structural features in kinases, also known as catalytic domains, consisting of $250-300$ amino acid residues and $12$ subdomains folding into a core structure.

Human Kinome

The complete collection of human protein kinases, which constitutes approximately $1.7\%$ of all human genes.

Serine, Threonine, and Tyrosine

The only three canonical amino acids in proteins that can be phosphorylated because they possess a hydroxyl group ($-OH$).

Conformational Changes (Phosphorylation)

Changes in a molecule's shape caused by phosphorylated residues being negatively charged and physically bigger, often resulting in enzymatic activation or inactivation.

Receptor Tyrosine Kinases (RTKs)

Cell-surface receptors with one membrane-spanning segment that directly phosphorylate specific tyrosines on themselves and on intracellular signalling proteins.

PDGF (Platelet Derived Growth Factor)

A growth factor ligand that binds to the PDGF receptor, causing the receptor to phosphorylate its own tyrosine residues to become active.

Anti-Phosphotyrosine Antibody [PY20]

A specific antibody used at $1\,\mu g/ml$ to detect the production of phosphorylated tyrosine by Western blotting.

Immunoglobulin (IgG)

The protein class of antibodies, characterized by light and heavy chains containing variable and constant regions and antigen-binding sites.

Receptor Dimerization

A key mechanism for activating RTKs, typically dependent on ligand binding to the receptor.

Asymmetric Mode of Activation (EGFR)

An activation mechanism for the Epidermal Growth Factor Receptor where an asymmetric arrangement of internal kinase domains causes an activating conformational change.

Phosphoryl Group Transfer Reaction

A reaction where $ATP$ acts as the phosphate donor to a substrate, producing $ADP$ and a hydrogen ion ($H^+$) as byproducts.

NIH 3T3

A mouse embryonic fibroblast cell line commonly used in experiments to demonstrate protein phosphorylation after treatment with growth factors like PDGF.