High impact information on Rab5a

• The functional association of Rab5a with dendritic and axonal early endosomes was assayed by electron microscopy after overexpression of wild-type and mutant Rab5a in cultured hippocampal neurons [1].
• The involvement of the small GTP-binding protein Rab5a in neuronal endocytosis [1].
• Using immunofluorescence, endogenous Rab5a was detected in axons and dendrites [1].
• Indeed, Rab5a co-immunoisolated with synaptophysin-containing vesicles, and antibodies against Rab5a labeled synaptic vesicle-like structures in nerve terminals [1].
• Rab5a is a small GTPase that regulates fusion of endocytic vesicles to early endosomes [1].

Biological context of Rab5a

• We investigated the roles of two Rab-family proteins, Rab3a and Rab5a, in hippocampal synaptic transmission using real-time fluorescence imaging [2].
• These results show a role for Rab5a in axonal and dendritic endocytosis, and the presence of Rab5a on synaptic vesicles indicates that the axonal endosomes participate in the biogenesis of these vesicles [1].

Anatomical context of Rab5a

• Overexpression of Rab5a promoted NK1R translocation to perinuclear sorting endosomes, whereas the GTP binding-deficient mutant Rab5aS34N caused retention of the NK1R in superficial early endosomes [3].
• Palmitoylation controls trafficking of GAD65 from Golgi membranes to axon-specific endosomes and a Rab5a-dependent pathway to presynaptic clusters [4].
• The results suggest that palmitoylation of GAD65 regulates the trafficking of the protein from Golgi membranes to an endosomal trafficking pathway in axons that is dependent on Rab5a and is required for the targeting of several synaptic vesicle proteins to presynaptic clusters [4].
• Here, we show that palmitoylated GAD65 colocalizes with the small GTP-binding protein Rab5a in Golgi membranes and in axons but not in dendrites [4].
• The purified synaptosomes exhibited specific enrichment of Rab3a, Rab5a, Ral, and several other GTPases [5].

Associations of Rab5a with chemical compounds

• SP induced translocation of the receptor into endosomes containing Rab5a immediately beneath the plasma membrane and then in a perinuclear location [6].
• Identification of Rab3-, Rab5a- and synaptobrevin II-like proteins in a preparation of rat kidney vesicles containing the vasopressin-regulated water channel [7].
• PT cells accumulated 109Cd7MT-1 in membrane vesicles associated with the late endo/lysosomal marker LAMP1 but less with the early endosomal marker Rab5a, which was abolished by chloroquine or LY-294002 [8].

Other interactions of Rab5a

• While overexpression of Rab3a did not affect vesicle recycling, overexpression of Rab5a reduced the recycling pool size by 50% [2].
• By contrast, Rab5a-positive/EEA1-positive somatodendritic giant endosomes containing the transferrin receptor were devoid of GAD65 [4].
• Dynamin and Rab5a-dependent trafficking is essential for NK1R resensitization but is not necessary for desensitization of signaling [6].
• Dynamin and Rab5a-dependent trafficking and signaling of the neurokinin 1 receptor [6].
• Rab3- and synaptobrevin II- but not Rab5a-like proteins were co-enriched with AQP-CD [7].

References