Type I protein exporter (IPR039421)

Short name: Type_I_exporter

Overlapping homologous superfamilies

Family relationships


Proteins in this entry are required for type I protein secretion and have an N-terminal ABC transporter type 1 transmembrane domain and a C-terminal P-loop containing nucleoside triphosphate hydrolase domain. The transmembrane domain forms a pore in the inner membrane and the ATP-binding domain is responsible for energy generation. Sequences are mainly from bacteria, but there are homologues from eukaryotes and archaea. Proteins in this entry include the following:

  • Lipid A export ATP-binding/permease protein MsbA, which is required for lipid A and possibly glycerophospholipid transport, and for biogenesis of the outer membrane in bacteria [PMID: 9575204]
  • Beta-(1-->2)glucan export ATP-binding/permease protein NdvA from nitrogen-fixing bacteria, which is required for beta-(1-->2)glucan export, essential for nodule formation in legume roots [PMID: 3042754]
  • Iron-sulfur clusters transporter ATM1, a yeast mitochondrial protein that exports Fe/S cluster-containing protein precursors and other mitochondrially synthesized proteins to the cytoplasm [PMID: 10406803]. The mammalian equivalents are the ATP-binding cassette sub-family B members 6, 7, 8 and 9, which are required for the transport of heme and porphyrin from the cytoplasm to the mitochondrion [PMID: 17006453]
  • Leukotoxin translocation ATP-binding protein LktB, required for leukotoxin export in Mannheimia haemolytica
  • Multidrug resistance protein 1, which exports xenobiotics, such as cytotoxic drugs, out of cells leading to tumour cell resistance to multiple drugs [PMID: 2876781]. The bacterial equivalents include multidrug resistance-like ATP-binding protein MdlA
  • Alpha-hemolysin translocation ATP-binding protein HlyB from E. coli, a component of the ABC transporter complex HlyBD required for the export of hemolysin [PMID: 2112747]
  • Phosphatidylcholine translocator ABCB4, required for lipid secretion in the bile, transporting phosphatidylcholine from the inner to the outer leaflet of the canalicular membrane bilayer into the canaliculi of hepatocytes [PMID: 7957936]
  • Bile salt export pump, required for the secretion of bile salts into the canaliculus of hepatocytes [PMID: 17264802]
  • Antigen peptide transporter 1, which is required for the transport of antigens from the cytoplasm to the endoplasmic reticulum for association with MHC class I molecules [PMID: 8955196]

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.