The α-subunit of the trimeric GTPase Go2 regulates axonal growth.
The Goα splice variants Go1α and Go2α are subunits of the most abundant G-proteins in brain, Go1 and Go2. Only a few interacting partners binding to Go1α have been described so far and splice variant-specific differences are not known. Using a yeast two-hybrid screen with constitutively active Go2α as bait, we identified Rap1GTPase activating protein (Rap1GAP) and Girdin as interacting partners of Go2α, which was confirmed by co-immunoprecipitation. Comparison of subcellular fractions from brains of wild type and Go2α-/- mice revealed no differences in the overall expression level of Girdin or Rap1GAP. However, we found higher amounts of active Rap1-GTP in brains of Go2α deficient mutants, indicating that Go2α may increase Rap1GAP activity, thereby effecting the Rap1 activation/deactivation cycle. Rap1 has been shown to be involved in neurite outgrowth and given a Rap1GAP-Go2α interaction, we found that the loss of Go2α affected axonal outgrowth. Axons of cultured cortical and hippocampal neurons prepared from embryonic Go2α-/- mice grew longer and developed more branches than those from wild-type mice. Taken together, we provide evidence that Go2α regulates axonal outgrowth and branching.
Center for Anatomy, Institute for Integrative Neuroanatomy, Functional Cell Biology, Charité-Universitätsmedizin Berlin, Germany.
Jens
J
Baron
Christian
C
Blex
Astrid
A
Rohrbeck
Sivarama Krishna
SK
Rachakonda
Lutz
L
Birnbaumer
Gudrun
G
Ahnert-Hilger
Irene
I
Brunk
D000818:Animals; D001369:Axons / Q000502:physiology*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000378:metabolism / Q000502:physiology*; D051960:GTP-Binding Protein alpha Subunit, Gi2 / Q000502:physiology*; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D021122:Protein Subunits / Q000502:physiology
D021122:Protein Subunits; D020558:GTP Phosphohydrolases; D051960:GTP-Binding Protein alpha Subunit, Gi2