Ras proteins undergo an incompletely understood trafficking process in the cell. 
Rasosomes are protein nanoparticles of 80-100 nm diameter that carry lipidated 
Ras isoforms (H-Ras and N-Ras) as well as their effectors through the cytoplasm 
and near the plasma membrane (PM). In this study, we identified the subcellular 
origin of rasosomes and how they spread Ras proteins through the cell. We found 
no dependency of rasosome formation on galectins, or on the GDP-/GTP-bound state 
of Ras. We found that significantly more rasosomes are associated with forms of 
Ras that are localized to the Golgi, namely N-Ras or the singly palmitoylated 
H-Ras mutant (C181S). To explore the possibility that rasosome originate from 
the Golgi, we used photoactivatable (PA)-GFP-H-Ras mutants and showed that 
rasosomes bud from the Golgi in a two-step mechanism. Newly released rasosomes 
first move in an energy-dependent directed fashion and then convert to randomly 
diffusing rasosomes. Dual fluorescence time-lapse imaging revealed the 
appearance of dually labeled rasosomes, indicating a dynamic exchange of 
cytoplasmic and PM-associated Ras with rasosome-associated Ras. Finally, higher 
levels of rasosomes correlate with higher levels of ERK phosphorylation, a key 
marker of Ras downstream signaling. We suggest that H-Ras and N-Ras proteins 
exchange with rasosomes that can function as carriers of palmitoylated Ras and 
its signals.