PROSITE documentation PDOC51776 [for PROSITE entry PS51776]

RH1 domain profile

The RH1 (RILP homology 1) protein-protein interaction domain is found in the following animal Rab36-binding proteins:

• Rab interacting lysosomal proteins (RILP),
• RILP-like 1 (RILP-L1),
• RILP-like 2 (RILP-L2),
• JNK-interacting protein 3 (JIP3),
• JNK-interacting protein 4 (JIP4).

It binds to the myosin Va globular tail domain (MyoVa-GTD) in mainly hydrophobic interactions.

The RH1 domain adopts an all-helical structure (see <PDB:4KP3>) and forms a homodimer with a four-helix bundle conformation to interact with MyoVa-GTD. The RH1 homodimer is structurally separated into two parts, the N-terminal four-helix bundle formed by α2 and α3N and the C-terminal coiled-coil formed by α3C. The four-helix bundle in the RH1 dimer is mainly stabilized by forming a hydrophobic core. The N-terminal small helix (α1) and its following loop pack on α2 from the same molecule and α3 from the neighboring molecule and thus contribute to the bundle stability. The RH1 homodimer is further strengthened by a coiled coil formed by the C-terminal half of the α3-helix [1].

The profile we developed covers the entire RH1 domain.