Protein Kinases and Signal Transduction Quiz

Akt Protein Mutation

• A mutated Akt protein, where the kinase is always active, will cause an increase in the phosphorylation of the Bad protein.

Protein Kinases in Signal Transduction

• The activation of many protein kinases in signal transduction pathways is an example of amplification.

Cholera Toxin and G Proteins

• The basic effect of cholera toxin on G proteins is signal amplification, rather than hydrolysis of GTP or activation of inhibitory proteins.

Protein Phosphorylation

• Enzyme activation, activation of protein kinase molecules and activation of receptor tyrosine kinases are involved in protein phosphorylation. Regulation of transcription factors is not involved.

mTOR Kinase

• Akt activation is stimulated by mTOR, mTOR stimulates cell growth, and mTOR is activated in the presence of cytokine. mTOR does not stimulate protein degradation and is not a tyrosine kinase.

Anaphase-Promoting Complex (APC)

• The target for ubiquitylation by the active anaphase-promoting complex (APC) is securin.

SH2 Domain

• P13 Kinase binds receptor phosphotyrosine residues via its SH2 domain.

Ubiquitin Protein

• Ubiquitin proteins are proteins that tag another protein for proteolysis.

Signaling Protein Domains

• A signaling protein made up of one SH2 domain and two SH3 domains is most likely an adaptor protein.

Cell Cycle Response to Go-Ahead Signal

• Mammalian cells complete the cell cycle and divide in response to a go-ahead signal.

Platelet-Released Substance

• Platelets release PDGF (platelet-derived growth factor) in the vicinity of an injury.

Cyclin

• Cyclin levels decrease when MPF (maturation-promoting factor) activity increases.

Yeast Signal Transduction

• Yeast cells produce signal molecules that directly interact with each other in signal transduction.

Neuron Response to Neurotransmitter

• The neurotransmitter acts as a signal molecule in a neuron's response.

Decline of MPF Activity

• The decline of MPF activity at mitosis is due to degradation of cyclin.

Spindle Checkpoint

• The spindle checkpoint determines chromosome attachment to the metaphase plate.

Insulin Receptor Activation

• The binding of two insulin molecules, causes dimerization following ligand binding, and results in activation of the PI-3 kinase pathway. Activation of the Ras/MAPK pathway is not a part of the initial activation process.

Phosphorylation of Amino Acids

• Protein kinases phosphorylate serine, threonine, and tyrosine.

Ras Activation

• Ras is activated early in the signal transduction pathway.

Cyclin-CDK Complexes

• Cyclin-CDK complexes control progression through the cell cycle.