Receptor Tyrosine Kinases (RTKs) and the MAPK Pathway

These flashcards cover key vocabulary and concepts related to Receptor Tyrosine Kinases and the MAPK signaling pathway as discussed in the lecture.

Receptor Tyrosine Kinases (RTKs)

A large group of receptors with intrinsic kinase activity involved in cellular signaling.

Mitogen Activated Protein Kinase (MAPK) pathway

A signaling pathway that mediates various cellular responses including growth and differentiation.

Epidermal growth factor (EGF)

A polypeptide that regulates growth, proliferation, and differentiation in cells.

Dimerization

The process by which two monomers, such as RTK receptors, bind together.

Trans autophosphorylation

The phosphorylation of tyrosine residues in one kinase by another kinase of the same kind after dimerization.

Intrinsic kinase activity

The ability of a receptor, such as an RTK, to initiate phosphorylation without the aid of another enzyme.

Ras

A small monomeric G protein that acts as a molecular switch in various signaling pathways.

GRB2

A cytosolic adaptor protein that links RTKs to downstream signaling proteins.

SOS (Son of Sevenless)

A guanine nucleotide exchange factor (GEF) that activates Ras by facilitating GDP-GTP exchange.

GDP

Guanosine diphosphate; the inactive form of Ras when bound to GDP.

GTP

Guanosine triphosphate; the active form of Ras when bound to GTP.

GAPs (GTPase Activating Proteins)

Proteins that accelerate the hydrolysis of GTP to GDP, thus turning signaling off.

GEFs (Guanine nucleotide Exchange Factors)

Proteins that promote the exchange of GDP for GTP, thus activating G proteins.

Tyrosine residues

Amino acid sites in receptors that are phosphorylated and serve as docking sites.

MAPK (Mitogen Activated Protein Kinase)

A family of serine/threonine kinases involved in transmitting signals from the cell surface to the nucleus.

MEK (MAP kinase/ERK kinase)

A kinase that acts downstream of Raf and activates MAPK through phosphorylation.

Raf (MAP kinase kinase kinase)

A serine/threonine kinase that is activated by Ras and initiates the MAPK cascade.

P90

A kinase activated by MAPK that further propagates the signaling cascade.

Transduction

The process of converting a signal from one form to another within a cell.

Regulatory 14-3-3 protein

A protein that binds to Raf, inhibiting its activity until Ras activates it.

Asymmetric dimer

A dimer formed by RTK monomers that interact unequally, leading to different kinase activities.

Phosphorylation

The addition of a phosphate group to an amino acid residue, often regulating protein activity.

Docking sites

Specific sites created by phosphorylation on receptors that allow binding of signaling intermediates.

Cell signaling pathways

Complex networks of interactions through which cells communicate internal and external signals.

Colorectal cancer and Ras

A type of cancer associated with mutations in the Ras gene, affecting cell proliferation.

Gene expression

The process by which information from a gene is used to create a functional product, like proteins.

Kinase cascade

A series of protein kinases that sequentially activate one another, amplifying a signal.

Specificity in signaling

The ability of signaling pathways to elicit specific responses based on the receptor and context.