These structures are thought to result from an imbalance between cargo incorporation in COPII-coated vesicles and the coat formation, and lowering the cargo load by inhibiting protein translation prevented their appearance.
We suggest that the eccentric position of the vesicle reflects the polarity of assembly, from initiation of coat formation to membrane pinching.
Our studies provide evidence for four protein modules that cooperate to drive coat formation, membrane invagination, actin-meshwork assembly, and vesicle scission during clathrin/actin-mediated endocytosis.
Recent in vivo experiments suggest that in the bacterium, Bacillus subtilis, the cue for the localization of the small sporulation protein, SpoVM, an essential factor in spore coat formation, is curvature of the bacterial plasma membrane.
Since actin coat formation occurs clearly after FACE (Figure 4B), a dependence of actin coat formation (and surfactant release) on FACE (and not vice versa) is strongly suggested.
The GTP-bound form of ARF proteins is required for vesicle coat formation.
The mechanisms of actin coat formation are complex and have been discussed in detail by others [40].
In addition to ARF, the p23 and the p24 type I membrane proteins play a role in coat formation and in cargo selection [21].
Therefore, it is possible that ACAP-A/B contribute to proper spore coat formation by mediating PSVs formation and/or trafficking dependent on the actin cytoskeleton.
Previous work showed that the cytoplasmic Ca2+ chelator BAPTA-AM inhibited the actin coat formation around fused vesicles, as well as surfactant release from LBs [18].
Coat formation, cargo capture, vesicle budding and dynamin-dependent scission involve a large number of proteins and protein interactions (see[5], [6] for review).
