scholarly journals A lipid transfer protein that transfers lipid

2007 ◽  
Vol 179 (1) ◽  
pp. 11-13 ◽  
Author(s):  
Tim P. Levine
Keyword(s):  
Lipid Transfer Protein ◽  
Adaptor Protein ◽  
Lipid Transfer ◽  
Lipid Transfer Proteins ◽  
Transfer Protein ◽  
Cell Biol ◽  
Circuitous Route

Very few lipid transfer proteins (LTPs) have been caught in the act of transferring lipids in vivo from a donor membrane to an acceptor membrane. Now, two studies (Halter, D., S. Neumann, S.M. van Dijk, J. Wolthoorn, A.M. de Maziere, O.V. Vieira, P. Mattjus, J. Klumperman, G. van Meer, and H. Sprong. 2007. J. Cell Biol. 179:101–115; D'Angelo, G., E. Polishchuk, G.D. Tullio, M. Santoro, A.D. Campli, A. Godi, G. West, J. Bielawski, C.C. Chuang, A.C. van der Spoel, et al. 2007. Nature. 449:62–67) agree that four-phosphate adaptor protein 2 (FAPP2) transfers glucosylceramide (GlcCer), a lipid that takes an unexpectedly circuitous route.

scholarly journals Movement of accessible plasma membrane cholesterol by the GRAMD1 lipid transfer protein complex

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Tomoki Naito ◽  
Bilge Ercan ◽  
Logesvaran Krshnan ◽  
Alexander Triebl ◽  
Dylan Hong Zheng Koh ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Intracellular Transport ◽  
Lipid Transfer Protein ◽  
Lipid Transfer ◽  
Lipid Transfer Proteins ◽  
Transfer Protein ◽  
Major Structural Component ◽  
Acute Increase ◽  
Transport Transition ◽  
Plasma Membrane Cholesterol

Cholesterol is a major structural component of the plasma membrane (PM). The majority of PM cholesterol forms complexes with other PM lipids, making it inaccessible for intracellular transport. Transition of PM cholesterol between accessible and inaccessible pools maintains cellular homeostasis, but how cells monitor the accessibility of PM cholesterol remains unclear. We show that endoplasmic reticulum (ER)-anchored lipid transfer proteins, the GRAMD1s, sense and transport accessible PM cholesterol to the ER. GRAMD1s bind to one another and populate ER-PM contacts by sensing a transient expansion of the accessible pool of PM cholesterol via their GRAM domains. They then facilitate the transport of this cholesterol via their StART-like domains. Cells that lack all three GRAMD1s exhibit striking expansion of the accessible pool of PM cholesterol as a result of less efficient PM to ER transport of accessible cholesterol. Thus, GRAMD1s facilitate the movement of accessible PM cholesterol to the ER in order to counteract an acute increase of PM cholesterol, thereby activating non-vesicular cholesterol transport.

In vivo and in vitro techniques in the diagnosis of lipid transfer protein sensitization

2013 ◽  
Vol 111 (6) ◽  
pp. 571-573 ◽  
Author(s):  
Felicia Berroa ◽  
Gabriel Gastaminza ◽  
Noemí Saiz ◽  
Julián Azofra ◽  
Pedro M. Gamboa ◽  
...  
Keyword(s):  
Lipid Transfer Protein ◽  
Lipid Transfer ◽  
In Vitro Techniques ◽  
Transfer Protein ◽  
Protein Sensitization

scholarly journals Regulation of secretory transport by protein kinase D–mediated phosphorylation of the ceramide transfer protein

2007 ◽  
Vol 178 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Tim Fugmann ◽  
Angelika Hausser ◽  
Patrik Schöffler ◽  
Simone Schmid ◽  
Klaus Pfizenmaier ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Lipid Transfer Protein ◽  
Membrane Integrity ◽  
Protein Kinase D ◽  
Lipid Transfer ◽  
Sphingomyelin Synthase ◽  
Transfer Protein ◽  
Secretory Transport ◽  
Phosphatidylinositol 4

Protein kinase D (PKD) has been identified as a crucial regulator of secretory transport at the trans-Golgi network (TGN). Recruitment and activation of PKD at the TGN is mediated by the lipid diacylglycerol, a pool of which is generated by sphingomyelin synthase from ceramide and phosphatidylcholine. The nonvesicular transfer of ceramide from the endoplasmic reticulum to the Golgi complex is mediated by the lipid transfer protein CERT (ceramide transport). In this study, we identify CERT as a novel in vivo PKD substrate. Phosphorylation on serine 132 by PKD decreases the affinity of CERT toward its lipid target phosphatidylinositol 4-phosphate at Golgi membranes and reduces ceramide transfer activity, identifying PKD as a regulator of lipid homeostasis. We also show that CERT, in turn, is critical for PKD activation and PKD-dependent protein cargo transport to the plasma membrane. Thus, the interdependence of PKD and CERT is key to the maintenance of Golgi membrane integrity and secretory transport.

scholarly journals VPS13: A lipid transfer protein making contacts at multiple cellular locations

2018 ◽  
Vol 217 (10) ◽  
pp. 3322-3324 ◽  
Author(s):  
Mingming Gao ◽  
Hongyuan Yang
Keyword(s):  
Lipid Transfer Protein ◽  
Lipid Transfer ◽  
Transfer Protein ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Cell Biol ◽  
Evolutionarily Conserved ◽  
Membrane Contact

The evolutionarily conserved VPS13 proteins localize to multiple membrane contact sites though their function and regulation has been elusive. Bean et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201804111) found that competitive adaptors control the different localizations of yeast Vps13p, while Kumar et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201807019) provide biochemical and structural evidence for VPS13 proteins in the nonvesicular transport of phospholipids.

scholarly journals Noncanonical regulation of phosphatidylserine metabolism by a Sec14-like protein and a lipid kinase

2020 ◽  
Vol 219 (5) ◽  
Author(s):  
Yaxi Wang ◽  
Peihua Yuan ◽  
Aby Grabon ◽  
Ashutosh Tripathi ◽  
Dongju Lee ◽  
...  
Keyword(s):  
Lipid Transfer Protein ◽  
Physical Interaction ◽  
Lipid Transfer ◽  
Uncharacterized Protein ◽  
Lipid Kinase ◽  
Transfer Protein ◽  
Transfer Activity ◽  
Phosphatidylinositol Transfer

The yeast phosphatidylserine (PtdSer) decarboxylase Psd2 is proposed to engage in a membrane contact site (MCS) for PtdSer decarboxylation to phosphatidylethanolamine (PtdEtn). This proposed MCS harbors Psd2, the Sec14-like phosphatidylinositol transfer protein (PITP) Sfh4, the Stt4 phosphatidylinositol (PtdIns) 4-OH kinase, the Scs2 tether, and an uncharacterized protein. We report that, of these components, only Sfh4 and Stt4 regulate Psd2 activity in vivo. They do so via distinct mechanisms. Sfh4 operates via a mechanism for which its PtdIns-transfer activity is dispensable but requires an Sfh4-Psd2 physical interaction. The other requires Stt4-mediated production of PtdIns-4-phosphate (PtdIns4P), where Stt4 (along with the Sac1 PtdIns4P phosphatase and endoplasmic reticulum–plasma membrane tethers) indirectly modulate Psd2 activity via a PtdIns4P homeostatic mechanism that influences PtdSer accessibility to Psd2. These results identify an example in which the biological function of a Sec14-like PITP is cleanly uncoupled from its canonical in vitro PtdIns-transfer activity and challenge popular functional assumptions regarding lipid-transfer protein involvements in MCS function.

Phosphatidylinositol-transfer protein and its homologues in yeast

2006 ◽  
Vol 34 (3) ◽  
pp. 377-380 ◽  
Author(s):  
P. Griac ◽  
R. Holic ◽  
D. Tahotna
Keyword(s):  
Membrane Trafficking ◽  
Diverse Group ◽  
Secretory Function ◽  
Lipid Transfer ◽  
Lipid Transfer Proteins ◽  
Transfer Protein ◽  
Phosphatidylinositol Transfer ◽  
Phosphatidylcholine Transfer Protein

Yeast Sec14p acts as a phosphatidylinositol/phosphatidylcholine-transfer protein in vitro. In vivo, it is essential in promoting Golgi secretory function. Products of five genes named SFH1–SFH5 (Sec Fourteen Homologues 1–5) exhibit significant sequence homology to Sec14p and together they form the Sec14p family of lipid-transfer proteins. It is a diverse group of proteins with distinct subcellular localizations and varied physiological functions related to lipid metabolism and membrane trafficking.

scholarly journals A model for a partnership of lipid transfer proteins and scramblases in membrane expansion and organelle biogenesis

2021 ◽  
Vol 118 (16) ◽  
pp. e2101562118
Author(s):  
Alireza Ghanbarpour ◽  
Diana P. Valverde ◽  
Thomas J. Melia ◽  
Karin M. Reinisch
Keyword(s):  
Lipid Transfer Protein ◽  
Membrane Dynamics ◽  
Lipid Homeostasis ◽  
In Vitro Assays ◽  
Lipid Transfer ◽  
Organelle Biogenesis ◽  
Lipid Transfer Proteins ◽  
Transfer Protein ◽  
Donor And Acceptor

The autophagy protein ATG2, proposed to transfer bulk lipid from the endoplasmic reticulum (ER) during autophagosome biogenesis, interacts with ER residents TMEM41B and VMP1 and with ATG9, in Golgi-derived vesicles that initiate autophagosome formation. In vitro assays reveal TMEM41B, VMP1, and ATG9 as scramblases. We propose a model wherein membrane expansion results from the partnership of a lipid transfer protein, moving lipids between the cytosolic leaflets of apposed organelles, and scramblases that reequilibrate the leaflets of donor and acceptor organelle membranes as lipids are depleted or augmented. TMEM41B and VMP1 are implicated broadly in lipid homeostasis and membrane dynamics processes in which their scrambling activities likely are key.

scholarly journals Who plays the ferryman: ATG2 channels lipids into the forming autophagosome

2019 ◽  
Vol 218 (6) ◽  
pp. 1767-1768 ◽  
Author(s):  
Nicholas T. Ktistakis
Keyword(s):  
Membrane Proteins ◽  
Lipid Transfer Protein ◽  
Protein Family ◽  
Lipid Transfer ◽  
Related Protein ◽  
Transfer Protein ◽  
Cell Biol

Expansion of the autophagosomal membrane requires a mechanism to supply lipids while excluding most membrane proteins. In this issue, Valverde et al. (2019. J. Cell Biol. https://doi.org/10.1083/jcb.201811139) identify ATG2, a member of the autophagy-related protein family, as a lipid transfer protein and provide important novel insights on how autophagosomes grow.

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