Adaptin

Adaptins are proteins that mediate the formation of vesicles by clathrin-coated pits, through interaction with membrane-bound receptors. There are several types of adaptin, each related to a different group of such receptors.

Adaptins show sequence similarity to some COPI subunits, thus they are thought to have a common evolutionary origin.

Adaptins cluster to form the AP2 complex.

The Adaptin complex is a heterotetramer consisting of two large adaptins (alpha or beta), a medium adaptin (mu), and a small adaptin (sigma):

• complex 1
  • AP1B1
  • AP1G1
  • AP1G2
  • AP1M1
  • AP1M2
  • AP1S1
  • AP1S2
  • AP1S3
• complex 2
  • AP2A1
  • AP2A2
  • AP2B1
  • AP2M1
  • AP2S1
• complex 3
  • AP3B1
  • AP3B2
  • AP3M1
  • AP3M2
  • AP3S1
  • AP3S2
• complex 4
  • AP4B1
  • AP4E1
  • AP4M1
  • AP4S1
• complex 5
  • complex 5 has been discovered at the university of Alberta, Canada, little is yet known of the internal constructs that make up the complex.

References

• Alberts, Johnson, Lewis, Raff, Roberts, Walter: Molecular Biology of the Cell, 4th edition (2002), Garland Science.