RTK

2022-04-13: reference:

RTK #

,

• This is NOT representative of every RTK, especially when you consider all the isoforms, but many of them do activate PI3K. I swear they basically all activate PI3K, Ras-RAF… and STAT-.

• A single unit with an extracellular ligand-binding domain. After binding, adjacent units form dimers: The cytoplasmic protein kinase domains then activate, and uses ATP to autophosphorylate the other unit on the Tyrosine residues.

  • Pretty sure the dimerization is covalent; apparently the inslin receptors form disulfides. Thus Methionine/Cysteine concentration is something to consider (cysteine-rich regions are characteristic of all RTK classes).
  • After phosphorylation, proteins including PI3K and Ras bind.

• Considering there’s 20 subclasses, I think I’ll worry about what they activate rather than RTK generally…

  • Their cascades can activate MAPKs.

Classes #

They all bind to Peptide Hormones.

• I (EGF receptor family) (ErbB family (ErbB-1 to -4))

  Ligand	EGFR	HER2	HER3	HER4
  EGF	+	-	-	-
  TGF-α 1	+	-	-	-
  NRG1	-	-	+	+
  neuregulin 2	-	-	+	+
  neuregulin 3	-	-	-	+
  neuregulin 4	-	-	-	+

• II (Insulin Receptor family)
  • Comes pre-dimerized out of the box!
• III (PDGF receptor family)
• IV (VEGF receptors family)
• V (FGF receptor family)
  • FGFR
• VI (CCK receptor family)
• VII (Neurotrophin/NGF receptor family)
  • Trk Receptor
    • TrkA (NGF)
    • TrkB (BDNF, NT-4, NT-3)
    • TrkC (NT-4, NT-3)
• VIII (HGF receptor family)
• IX (Eph receptor family)
• X (AXL receptor family)
• XI (TIE receptor family)
• XII (RYK receptor family)
• XIII (DDR receptor family)
• XIV (RET receptor family)
• XV (ROS receptor family)
• XVI (LTK receptor family)
• XVII (ROR receptor family)
• XVIII (MuSK receptor family)
• XIX (LMR receptor)
• XX (Undetermined)