Question

A tyrosine kinase receptor is different from a G-protein linked receptor in that it can trigger _________ at the same time. When both __________ are in their receptor sites, the molecules form a dimer – two molecules joined together. ATP is converted to ADP and the ___________ gets attached to the tyrosine molecules. The addition of the ____________ causes a cascade of cellular responses.

Answer 1

A tyrosine kinase receptor can simultaneously trigger several cellular responses by forming a dimer when signaling molecules bind. Phosphate groups are then attached to tyrosine residues, initiating cellular responses. These responses are later terminated by phosphatases removing the phosphate groups.

Step-by-step explanation:

A tyrosine kinase receptor is different from a G-protein linked receptor in that it can trigger multiple cellular responses at the same time. When both signaling molecules are in their receptor sites, the molecules form a dimer – two molecules joined together. ATP is converted to ADP and the phosphate groups get attached to the tyrosine molecules. The addition of the phosphate groups causes a cascade of cellular responses.

Understanding Tyrosine Kinase Receptors :

Receptor tyrosine kinases are enzyme-linked receptors that have a crucial role in cellular signaling. They possess a single helical transmembrane region, with extracellular and intracellular domains. Upon binding of a signaling molecule, such as growth factors like Epidermal Growth Factor (EGF), to the extracellular domain, the receptor undergoes dimerization. This activates the intracellular kinase domains, which then transfer phosphate groups from ATP to tyrosine residues on the receptor itself, a process known as autophosphorylation. These phosphorylated tyrosine residues then serve as docking sites for other signaling proteins within the cell, which in turn trigger downstream cellular responses such as cell division, differentiation, or apoptosis. When the signaling needs to be terminated, phosphatases remove the phosphate groups from the phosphotyrosine residues, thus ending the cellular response.

Answer 2

1. multiple pathways
2. ligands/signaling molecules
3. inorganic phosphate
4. inactive relay proteins

Step-by-step explanation:

Receptor Tyrosine Kinase:

• Receptor tyrosine kinase (RTK) is the largest class of enzyme linked cell surface receptors.
• When a growth factor or a ligand binds to two neighboring RTK receptors, the two receptors bind together and form a dimer.
• This change in the conformation of the RTKs activates the associated tyrosine kinase enzymes.
• Tyrosine kinases break down ATP to ADP and phosphorylate the RTKs. Cross phosphorylation between the receptors helps activate multiple tyrosine kinases on the neighboring RTK.
• Once phosphorylated, the cytoplasmic ends of the RTKs are available for docking by relay proteins or signaling molecules with an SH-2 domain.