The bacterial toxins that cause cholera and pertussis are enzymes that catalyze transfer of the ADP ribose moiety.

TLS Online TPP Program

#Id: 9615

#XL - T Zoology

Four related EGF receptors participate in signaling by the many members of EGF family :

In the mouse - Erb-B1, 2, 3, and 4

In humans - HER 1, 2, 3, and 4

TLS Online TPP Program

#Id: 9616

#XL - T Zoology

Homodimerization

HER1 directly binds EGF which leads to formation of a homodimer of the HER1 extracellular domain

TLS Online TPP Program

#Id: 9617

#XL - T Zoology

TLS Online TPP Program

#Id: 9618

#XL - T Zoology

Neuregulins 1, 2, 3, and 4, bind to HER4 that, like HER1, can also form homodimers.

TLS Online TPP Program

#Id: 9619

#XL - T Zoology

HER2 (mouse Erb-B2), cannot bind any ligand, it can form a heterodimer with ligand-activated HER1, HER3, or HER4 (Erb-B1, 3, or 4)

TLS Online TPP Program

#Id: 9620

#XL - T Zoology

HER3 (Erb-B3) can bind ligands but lacks a functional kinase domain and can signal only when heterodimerizes with HER2 (Erb-B2