Rabaptin coiled-coil domain (IPR018514)

Short name: Rabaptin_coiled-coil

Overlapping homologous superfamilies


Domain relationships



Regeneration of injured axons at neuromuscular junctions has been assumed to be regulated by extra-cellular factors that promote neurite outgrowth. A novel neurite outgrowth factor from chick denervated skeletal muscle has been cloned and characterised. The protein, termed neurocrescin (rabaptin), has been shown to be secreted in an activity-dependent fashion [PMID: 9427343].

Rabaptin is a 100kDa coiled-coil protein that interacts with the GTP form of the small GTPase Rab5, a potent regulator of endocytic transport [PMID: 8521472]. It is mainly cytosolic, but a fraction co-localises with Rab5 to early endosomes. Rab5 recruits rabaptin-5 to purified early endosomes in a GTP-dependent manner, demonstrating functional similarities with other members of the Ras superfamily. Immunodepletion of rabaptin-5 from cytosol strongly inhibits Rab5-dependent early endosome fusion. Thus, rabaptin-5 is a Rab effector required for membrane docking and fusion.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005096 GTPase activator activity
GO:0008083 growth factor activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.