GTP-binding nuclear protein Ran
Developmental stage
Expression is low at 2 hpf and starts to increase steadily after 12 hpf to reach adult levels at 72 hpf.
Function
GTPase involved in nucleocytoplasmic transport, participating both to the import and the export from the nucleus of proteins and RNAs. Switches between a cytoplasmic GDP- and a nuclear GTP-bound state by nucleotide exchange and GTP hydrolysis. Nuclear import receptors such as importin beta bind their substrates only in the absence of GTP-bound RAN and release them upon direct interaction with GTP-bound RAN, while export receptors behave in the opposite way. Thereby, RAN controls cargo loading and release by transport receptors in the proper compartment and ensures the directionality of the transport. Interaction with RANBP1 induces a conformation change in the complex formed by XPO1 and RAN that triggers the release of the nuclear export signal of cargo proteins. RAN (GTP-bound form) triggers microtubule assembly at mitotic chromosomes and is required for normal mitotic spindle assembly and chromosome segregation. Required for normal progress through mitosis.
Sequence Similarities
Belongs to the small GTPase superfamily. Ran family.
Tissue Specificity
Ubiquitous, with the highest expression in ovary, muscle, eye and brain.
Cellular localization
- Nucleus
- Nucleus envelope
- Cytoplasm
- Cytosol
- Cytoplasm
- Predominantly nuclear during interphase. Becomes dispersed throughout the cytoplasm during mitosis (By similarity).
Alternative names
GTP-binding nuclear protein Ran, GTPase Ran, Ras-related nuclear protein, ran