Phosphatidylinositol transfer proteins mediate the monomeric transport of lipids by shielding a lipid from the aqueous environment and binding the lipid in a hydrophobic cavity. Drosophila melanogaster (taxid: 7227)
>sp|Q54VC7|PITP3_DICDI Phosphatidylinositol transfer protein 3 OS=Dictyostelium discoideum GN=pitC PE=3 SV=1
Phosphatidylinositol transfer proteins mediate the monomeric transport of lipids by shielding a lipid from the aqueous environment and binding the lipid in a hydrophobic cavity. Able to transfer phosphatidylinositol in vitro. Isoform 2 specifically binds to phosphatidylinositol but not to other phospholipids and may play a role in the phosphoinositide-mediated signaling in the neural development.
Mus musculus (taxid: 10090)
>sp|Q9UKF7|PITC1_HUMAN Cytoplasmic phosphatidylinositol transfer protein 1 OS=Homo sapiens GN=PITPNC1 PE=1 SV=2
Phosphatidylinositol transfer proteins mediate the monomeric transport of lipids by shielding a lipid from the aqueous environment and binding the lipid in a hydrophobic cavity. Able to transfer phosphatidylinositol in vitro.
Homo sapiens (taxid: 9606)
>sp|Q00169|PIPNA_HUMAN Phosphatidylinositol transfer protein alpha isoform OS=Homo sapiens GN=PITPNA PE=1 SV=2
>gi|66557640|ref|XP_624564.1| PREDICTED: phosphatidylinositol transfer protein alpha isoform [Apis mellifera] gi|380026307|ref|XP_003696893.1| PREDICTED: phosphatidylinositol transfer protein alpha isoform-like [Apis florea]
This subgroup includes the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain of mammalian Class 1 phosphatidylinositol transfer proteins (PITPs), PITPNA/PITPalpha and PITPNB/PITPbeta, Drosophila vibrator, and related proteins. These are single domain proteins belonging to the PITP family of lipid transfer proteins, and to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. In addition, PITPNB transfers sphingomyelin in vitro, with a low affinity. PITPNA is found chiefly in the nucleus and cytoplasm; it is enriched in the brain and predominantly localized in the axons. A reduced expression of PITPNA contributes to the neurodegenerative phenotype of the mouse vibrator mutation. The role of PITPNA in vivo may be to provide PtdIns for localized PI3K-dependent signaling, thereby controlling the polarized extension of axonal processes. PITPNA homozygous null mice die soon after birth from complicated organ failure, including intestinal and hepatic steatosis, hypoglycemia, and spinocerebellar disease. PITPNB is associated with the Golgi and ER, and is highly expressed in the liver. Deletion of the PITPNB gene results in embryonic lethality. The PtdIns and PtdCho exchange activity of PITPNB is required for COPI-mediated retrograde transport from the Golgi to the ER. Drosophila vibrator localizes to the ER, and has an essential role in cytokinesis during mitosis and meiosis. Length = 258
>gnl|CDD|176857 cd07815, SRPBCC_PITP, Lipid-binding SRPBCC domain of Class I and Class II Phosphatidylinositol Transfer Proteins
This family includes the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain of the phosphatidylinositol transfer protein (PITP) family of lipid transfer proteins. This family of proteins includes Class 1 PITPs (PITPNA/PITPalpha and PITPNB/PITPbeta, Drosophila vibrator and related proteins), Class IIA PITPs (PITPNM1/PITPalphaI/Nir2, PITPNM2/PITPalphaII/Nir3, Drosophila RdgB, and related proteins), and Class IIB PITPs (PITPNC1/RdgBbeta and related proteins). The PITP family belongs to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. Class III PITPs, exemplified by the Sec14p family, are found in yeast and plants but are unrelated in sequence and structure to Class I and II PITPs and belong to a different superfamily. Length = 251
>gnl|CDD|111058 pfam02121, IP_trans, Phosphatidylinositol transfer protein
Score = 58.3 bits (141), Expect = 8e-12
Identities = 24/46 (52%), Positives = 28/46 (60%)
Query: 42 VHDLPADKLKVREVVHIDIGNDPVSAGDYKETEDPAKFKSEKTGRG 87
V +L K R + +IDI D VS+GDYK EDP F S KTGRG
Sbjct: 125 VFNLSPKDWKTRIIDYIDIVRDQVSSGDYKAEEDPKLFHSVKTGRG 170
Along with the structurally unrelated Sec14p family (found in pfam00650), this family can bind/exchange one molecule of phosphatidylinositol (PI) or phosphatidylcholine (PC) and thus aids their transfer between different membrane compartments. There are three sub-families - all share an N-terminal PITP-like domain, whose sequence is highly conserved. It is described as consisting of three regions. The N-terminal region is thought to bind the lipid and contains two helices and an eight-stranded, mostly antiparallel beta-sheet. An intervening loop region, which is thought to play a role in protein-protein interactions, separates this from the C-terminal region, which exhibits the greatest sequence variation and may be involved in membrane binding. PITP alpha has a 16-fold greater affinity for PI than PC. Together with PITP beta, it is expressed ubiquitously in all tissues. Length = 254
>gnl|CDD|176899 cd08890, SRPBCC_PITPNC1_like, Lipid-binding SRPBCC domain of mammalian PITPNC1,and related proteins (Class IIB PITPs)
This subgroup includes the N-terminal SRPBCC (START/RHO_alpha_C /PITP /Bet_v1/CoxG/CalC) domain of mammalian Class IIB phosphatidylinositol transfer protein (PITP), PITPNC1/RdgBbeta, and related proteins. These are metazoan proteins belonging to the PITP family of lipid transfer proteins, and to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. Mammalian PITPNC1 contains an amino-terminal SRPBCC PITP-like domain and a short carboxyl-terminal domain. It is a cytoplasmic protein, and is ubiquitously expressed. It can transfer phosphatidylinositol (PtdIns) in vitro with a similar ability to other PITPs. Length = 250
>gnl|CDD|176898 cd08889, SRPBCC_PITPNM1-2_like, Lipid-binding SRPBCC domain of mammalian PITPNM1-2 and related proteins (Class IIA PITPs)
This subgroup includes an N-terminal SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain of mammalian Class II phosphatidylinositol transfer protein (PITPs), PITPNM1/PITPalphaI/Nir2 (PYK2 N-terminal domain-interacting receptor2) and PITPNM2/PITPalphaII/Nir3), Drosophila RdgB, and related proteins. These are membrane associated multidomain proteins belonging to the PITP family of lipid transfer proteins, and to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. Ablation of the mouse gene encoding PITPNM1 results in early embryonic death. PITPNM1 is localized chiefly to the Golgi apparatus, and under certain conditions translocates to the lipid droplets. Targeting to the latter is dependent on a specific threonine residue within the SRPBCC domain. PITPNM1 plays a part in Golgi-mediated transport. It regulates diacylglycerol (DAG) production at the trans-Golgi network (TGN) via the CDP-choline pathway. Drosophila RdgB, the founding member of the PITP family, is implicated in the visual and olfactory transduction. RdgB is required for maintenance of ultra structure in photoreceptors and for sensory transduction. The mouse PITPNM1 gene rescues the phenotype of Drosophila rdgB mutant flies. In addition to the SRPBCC domain, PITPNM1 and -2 contain a Rho-inhibitory domain (Rid), six hydrophobic stretches, a DDHD calcium binding region, and a C-terminal tyrosine kinase Pyk2-binding / HAD-like phosphohydrolase domain. PITPNM1 has a role in regulating cell morphogenesis through its Rho inhibitory domain (Rid). This SRPBCC_PITPNM1-2_like domain model includes the first 52 residues of the 224 residues Rid (Rho-inhibitory domain). Length = 260
This family includes the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain of the phosphatidylinositol transfer protein (PITP) family of lipid transfer proteins. This family of proteins includes Class 1 PITPs (PITPNA/PITPalpha and PITPNB/PITPbeta, Drosophila vibrator and related proteins), Class IIA PITPs (PITPNM1/PITPalphaI/Nir2, PITPNM2/PITPalphaII/Nir3, Drosophila RdgB, and related proteins), and Class IIB PITPs (PITPNC1/RdgBbeta and related proteins). The PITP family belongs to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns
>cd08889 SRPBCC_PITPNM1-2_like Lipid-binding SRPBCC domain of mammalian PITPNM1-2 and related proteins (Class IIA PITPs)
This subgroup includes an N-terminal SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain of mammalian Class II phosphatidylinositol transfer protein (PITPs), PITPNM1/PITPalphaI/Nir2 (PYK2 N-terminal domain-interacting receptor2) and PITPNM2/PITPalphaII/Nir3), Drosophila RdgB, and related proteins. These are membrane associated multidomain proteins belonging to the PITP family of lipid transfer proteins, and to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. Ablation of the mouse gene en
>cd08890 SRPBCC_PITPNC1_like Lipid-binding SRPBCC domain of mammalian PITPNC1,and related proteins (Class IIB PITPs)
This subgroup includes the N-terminal SRPBCC (START/RHO_alpha_C /PITP /Bet_v1/CoxG/CalC) domain of mammalian Class IIB phosphatidylinositol transfer protein (PITP), PITPNC1/RdgBbeta, and related proteins. These are metazoan proteins belonging to the PITP family of lipid transfer proteins, and to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. Mammalian PITPNC1 contains an amino-terminal SRPBCC PITP-like domain and a short carboxyl-terminal domain. It is a cytoplasmic protein, and is ubiquitously
>cd08888 SRPBCC_PITPNA-B_like Lipid-binding SRPBCC domain of mammalian PITPNA, -B, and related proteins (Class I PITPs)
This subgroup includes the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain of mammalian Class 1 phosphatidylinositol transfer proteins (PITPs), PITPNA/PITPalpha and PITPNB/PITPbeta, Drosophila vibrator, and related proteins. These are single domain proteins belonging to the PITP family of lipid transfer proteins, and to the SRPBCC domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. In vitro, PITPs bind phosphatidylinositol (PtdIns), as well as phosphatidylcholine (PtdCho) but with a lower affinity. They transfer these lipids from one membrane compartment to another. The cellular roles of PITPs include inositol lipid signaling, PtdIns metabolism, and membrane trafficking. In addition, PITPNB transfers sphingomyelin in vitro, with a low affinity. PITPNA is found chiefly in the nucleus and cy
>PF02121 IP_trans: Phosphatidylinositol transfer protein; InterPro: IPR001666 Phosphatidylinositol transfer protein (PITP) is a ubiquitous cytosolic protein, thought to be involved in transport of phospholipids from their site of synthesis in the endoplasmic reticulum and Golgi to other cell membranes []
More recently, PITP has been shown to be an essential component of the polyphosphoinositide synthesis machinery and is hence required for proper signalling by epidermal growth factor and f-Met-Leu-Phe, as well as for exocytosis. The role of PITP in polyphosphoinositide synthesis may also explain its involvement in intracellular vesicular traffic [].; GO: 0006810 transport, 0005622 intracellular; PDB: 1T27_A 1KCM_A 2A1L_A 1UW5_C.
