GTPase-activating protein (GAP) that most effectively accelerates the intrinsic GTPase activity of Ypt/Rab-type GTPase YPT7 involved in vacuole docking and fusion (PubMed:10091609, PubMed:11210571). It is also active, but to a lesser extent, on YPT31, YPT32, YPT1, YPT6 and SEC4 (PubMed:10091609, PubMed:11210571). Provides a catalytic arginine (arginine finger) in trans to accelerate the GTP hydrolysis rate of the substrate GTPase (Probable). Present with 2460 molecules/cell in log phase SD medium.