Recombinant Bacillus subtilis Uncharacterized protein ypbR (ypbR), partial

Mediates lipid mixing of vesicles and full mixing of their contents in the absence and presence of GTP. Tethers and mixes small vesicles better than larger ones, indicating a curvature preference. GTP slows down DynA-mediated lipid fusion, perhaps controlling its activity. Prefers phospholipid composition close to the B.subtilis membrane; requires phosphatidylglycerol for fusion has no activity on pure phosphatidylethanolamine vesicles. Regulates membrane lipid diffusion. Required to prevent membrane damage when exposed to low levels of membrane-damaging antibiotics or to bacteriophage. Probably surveys the cell membrane for stress; localizes to sites of membrane damage (treatment with nisin) and forms foci in cells treated with pore-forming compounds (CCCP). May assist membrane repair, possibly by membrane tethering and fusion. Probably functions both in early and late cell division, affects the proper formation of the FtsZ ring. Plays a non-redundant role with flottilin (floT) in membrane dynamics and cell shape. Probably able to bend membranes. Tethers liposomes and mediates their fusion; this does not require GTPase activity or the presence of GTP. Both GTPase domains (dynamin-type G) are required for GTPase activity.; Has intrinsic affinity for membranes and membrane distortion capability; causes tubulation and membrane distortion when expressed in a Drosophila cell line.