Exhibits selective intermembrane transfer of ceramide-1-phosphate (C1P) and phytoceramide-1-phosphate (PubMed:24412362, PubMed:28011644). Does not transport ceramide (Cer) or GalCer, suggesting a requirement for phosphate in the headgroup for functionality (PubMed:24412362). Transports in vitro sphingosine, but not glycosphingolipids (PubMed:11850411). Has also some in vitro activity with sphingomyelin, a lipid not detected in plant tissues (PubMed:18657186). The transport function may be not directly involved in regulating cell death. Rather, perturbations in the function of ACD11 or related components could be monitored by R-proteins, which then mediate defense and programmed cell death (PCD), as proposed in the guard hypothesis (Probable). C1P transfer is stimulated by phosphatidylserine in C1P source vesicles (PubMed:28011644). Regulates autophagy, inflammasome mediated IL1B and IL18 processing, and pyroptosis, but not apoptosis (PubMed:28011644). Interacts with BPA1, PRA1F2 and PRA1F3 (PubMed:18845362). Constitutive expression of defense-related genes that accompany the hypersensitive response normally triggered by avirulent pathogens. Induction of growth inhibition, premature leaf chlorosis and defense-related programmed cell death (PCD) at the early seedling stage, leading to a lethal phenotype before flowering (PubMed:11850411, PubMed:15923330). Large increase of cell death inducer phytoceramide (PubMed:24412362). The clustered Lys-64/Arg-99/Arg-103 residues form a positively charged triad ideally arranged for binding phosphate, explaining the inability to bind sugar headgroups and transfer glycoproteins. Belongs to the GLTP family.