Golgi-Resident Gαo Promotes Protrusive Membrane Dynamics

Abstract

To form protrusions like neurites, cells must coordinate their induction and growth. The first requires cytoskeletal rearrangements at the plasma membrane (PM), the second requires directed material delivery from cell's insides. We find that the Gαo-subunit of heterotrimeric G proteins localizes dually to PM and Golgi across phyla and cell types. The PM pool of Gαo induces, and the Golgi pool feeds, the growing protrusions by stimulated trafficking. Golgi-residing KDELR binds and activates monomeric Gαo, atypically for G protein-coupled receptors that normally act on heterotrimeric G proteins. Through multidimensional screenings identifying > 250 Gαo interactors, we pinpoint several basic cellular activities, including vesicular trafficking, as being regulated by Gαo. We further find small Golgi-residing GTPases Rab1 and Rab3 as direct effectors of Gαo. This KDELR → Gαo → Rab1/3 signaling axis is conserved from insects to mammals and controls material delivery from Golgi to PM in various cells and tissues.

Gαo (GNAO1) encephalopathies: plasma membrane vs. Golgi functions

“…However, an increasing amount of data indicate that they also work at different cellular compartments, especially at the Golgi apparatus [ 6 ]. Recently, we identified >250 proteins as potential Gαo interacting partners, and subsequently uncovered a non-canonical Gαo signaling involved in the regulation of vesicular trafficking at the Golgi [ 7 ]. We showed that two pools of Gαo – at the PM and Golgi – coexist and act coordinately in cellular processes such as neuritogenesis: the PM Gαo locally initiates neurite formation, and the Golgi Gαo ensures material delivery for neurites to grow (Figure 1 ).…”

Antagonistic PCP Signaling Pathways in the developing Drosophila eye

“…Trimeric G-proteins frequently regulate small GTPases of the Rho family 37 , 38 and in this regard RhoA appeared as a possible Go effector since it has been implicated in PCP signaling 19 . RhoA loss-of-function clones in wild-type eyes show no chirality defects 14 , but in R3/4 mosaic analyses in fz − eyes, the RhoA mutant cell was significantly biased to the R3 fate (Fig.…”

Local and substrate-specific S-palmitoylation determines subcellular localization of Gαo

“…Overall, we identified more than 800 sequences containing the desired Nt 7 signature (Supplementary We asked whether consensus sequences might emerge from the Gα subunits among each category. As available databases are biased towards certain clades, we first selected unique hexapeptides with the signature M 1 GXXX[ACGST] 6 . When an identical combination within positions 3-5 was found, we selected the sequence with the most frequent residue at position 7 for this analysis.…”

“…The mRFP-Gβ1 construct was created by exchanging the AgeI/BsrGI mCerulean sequence from mCerulean-Gβ1 57 with the corresponding from pmRFP-C1 (Claudia Stuermer, University of Konstanz). Similarly, the mRFP-Gγ3 was created by substituting the AgeI/BsrGI GFP sequence in the GFP-Gγ3 plasmid 6 with the mRFP sequence. The mRFP-Lact-C2 was done by replacing the AgeI/BsrGI GFP sequence from GFP-Lact-C2 (kindly provided by Gregory Fairn; University of Toronto) with the sequence from pmRFP-C1.…”