8.A.6 The Auxiliary Nutrient Transporter (ANT) Family A single functionally characterized protein of 2958aas, YLR087c of Saccharomyces cerevisiae (CSF1p) appears to function as an auxiliary protein, stimulating nutrient uptake at low temperatures. The protein is required for growth and sugar fermentation only at low temperatures (i.e. 4°). A CSF1 disruptant mutant exhibited about 4x lower glucose and L-leucine uptake rates than the wild type parent, but at 30°, the two strains showed the same rates of uptake. These results suggest that CSF1p associates with unidentified plasma membrane transporters to stimulate their activities at low temperatures. The protein shows limited sequence similarity near its N-terminus (residues 21-704) to comparable N-terminal regions in (1) a protein of 2042aas from Drosophila melanogaster (gbAE003653) and (2) another protein of 4158aas from Caenorabditis elegans (gbAC024791). CSF1p might be a regulator of certain nutrient transporters.
References:
Jeng, E.E., V. Bhadkamkar, N.U. Ibe, H. Gause, L. Jiang, J. Chan, R. Jian, D. Jimenez-Morales, E. Stevenson, N.J. Krogan, D.L. Swaney, M.P. Snyder, S. Mukherjee, and M.C. Bassik. (2019). Systematic Identification of Host Cell Regulators of Legionella pneumophila Pathogenesis Using a Genome-wide CRISPR Screen. Cell Host Microbe 26: 551-563.e6.
Kane, M.S., C.J. Diamonstein, N. Hauser, J.F. Deeken, J.E. Niederhuber, and T. Vilboux. (2019). Endosomal trafficking defects in patient cells with biallelic variants. Genes Dis 6: 56-67.
Tokai, M., H. Kawasaki, Y. Kikuchi, and K. Ouchi. (2000). Cloning and characterization of the CSF1 gene of Saccharomyces cerevisiae, which is required for nutrient uptake at low temperature. J. Bacteriol. 182: 2865-2868.
Toulmay, A., F.B. Whittle, J. Yang, X. Bai, J. Diarra, S. Banerjee, T.P. Levine, A. Golden, and W.A. Prinz. (2022). Vps13-like proteins provide phosphatidylethanolamine for GPI anchor synthesis in the ER. J. Cell Biol. 221:.
Examples:
TC#	Name	Organismal Type	Example
8.A.6.1.1	Cold-sensitive fermentation (CSF1) protein of 2985 aas. It is a tube-forming lipid transport protein which provides phosphatidylethanolamine for glycosylphosphatidylinositol (GPI) anchor synthesis in the endoplasmic reticulum (Toulmay et al. 2022). It is required for the glucose and other nutrients uptake at low temperature (Tokai et al. 2000).	Yeast	CSF1 of Saccharomyces cerevisiae

8.A.6.1.2	Bridge-like lipid transfer protein family member 1 C-terminal domain-containing protein, Lpd-1, of 4018 aas and at least one N-terminal TMS, but several additional potential TMSs. It is a tube-forming lipid transport protein which provides phosphatidylethanolamine for glycosylphosphatidylinositol (GPI) anchor synthesis in the endoplasmic reticulum. It also plays a role in endosomal trafficking and endosome recycling, and is involved in the actin cytoskeleton and cilia structural dynamics (Kane et al. 2019). It acts as regulator of phagocytosis (Jeng et al. 2019).		Lpd-1 of Caenorhabditis elegans

8.A.6.1.3	Bridge-like lipid transfer protein family member 1, Bltp1, of 5005 aas with one N-terminal TMS plus possibly additional TMSs elsewhere. It is a tube-forming lipid transport protein which provides phosphatidylethanolamine for glycosylphosphatidylinositol (GPI) anchor synthesis in the endoplasmic reticulum, and it plays a role in endosomal trafficking and endosome recycling. It may also be involved in the actin cytoskeleton and cilia structural dynamics (Kane et al. 2019) while also acting as a regulator of phagocytosis (Jeng et al. 2019).		Bltp1 of Homo sapiens