Sec14 is a cytosolic protein found in yeast (Saccharomyces cerevisiae) which plays a role in the regulation of several cellular functions, specifically those related to intracellular transport. Encoded by the Sec14 gene, Sec14p may transport phosphatidylinositol and phosphatidylcholine produced in the endoplasmic reticulum and the Golgi body to other cellular membranes. Additionally, Sec14p potentially plays a role in the localization of lipid raft proteins. Sec14p is an essential gene in yeast, and is homologous in function to phosphatidylinositol transfer protein in mammals. A conditional mutant with non-functional Sec14p presents with Berkeley bodies and deficiencies in protein secretion. Structure Sec14p exhibits two distinct domains, made up of twelve ⍺-helices, six 𝛽-strands, and eight 310-helices. The phospholipid binding domain of Sec14p consists of a hydrophobic pocket within the carboxy-terminal domain. Function The function of Sec14p has largely been determined through the phenotype presented in conditional Sec14p mutants. As Sec14p is an essential gene, Sec14p knockouts must be performed in yeast strains with several other mutations conveying viability without functional Sec14p. In this knockout mutant, certain proteins destined for export accumulate in non-vesicular compartments of the cell. From this, functional Sec14p likely plays a role in some pathway responsible for cellular export of certain proteins. Protein accumulation in a Sec14p knockout is also accompanied by the formation of Berkeley bodies, an organelle unique to yeast consisting of cytoplasm enclosed by a double membrane. The presence of Berkeley bodies in Sec14p knockouts suggests Sec14p regulates or is involved in the uptake and reabsorption of certain vesicles by other organelles, such as the Golgi body, or the plasma membrane of the cell. The accumulation of both Berkeley bodies and proteins in the cytosol indicate that Sec14p is involved in the formation and degradation of anterograde vesicles of certain proteins. Molecular In vitro, Sec14p has been demonstrated to catalyze the transport of phosphatidylinositol (PtdIns) and phosphatidylcholine (PtdCho) between lipid membranes. It has been suggested that the ability to bind PtdIns and PtdCho aids the intracellular transport function and regulation of Sec14p. This property may arise from potential transport of membrane lipids between the endoplasmic reticulum (ER) and the Golgi body by Sec14p to maintain an equilibrium in the membrane lipid concentration. Sec14p is thought to achieve phospholipid transport through phospholipid exchange. The protein-phospholipid complex associates with a lipid bilayer, discharges the bound phospholipid into the bilayer, and upon recognition of another membrane bound phospholipid, extracts the