Fibroblast Growth Factor (FGF) and Receptor Tyrosine Kinase (RTK) Signaling

FGF

Fibroblast Growth Factor; Family of signaling proteins that regulate cell proliferation

TKR

Tyrosine Kinase Receptor ; Receptor that acts as an on/off switch for cellular processes

Extracellular domain will ….

Bind the ligand

Ligand

Molecule that binds to a receptor; Signaling protein

Intracellular domain is a….

Kinase

Kinases

Phosphorylate proteins by transferring a phosphate from ATP (ATP —> ADP)

Step 1

FGF ligand binds to FGF receptor (FGFRs/TKR) —> Dimeration of receptors

Dimeration

Becoming a dimer (when 2 molecules join to form a larger, single unit)

Step 2

Activation of FGFRs

ATP binds to the kinase domain of the FGFRs

Step 3

Active FGFRs can phosphorylate downstream proteins

ATP stays bound to the kinase domain

Phosphorylation

An on/off switch for proteins

Step 4

Phosphorylation cascade

Downstream proteins phosphorylate other downstream proteins and so on

Step 5 (sometimes)

Activation of transcription factors in the nucleus that can activate or repress transcription of different genes