High impact information on VAC14

• In both the absence and presence of Vac7p, the Vac14p-Fig4p complex controls the hyperosmotic shock-induced increase in PI3,5P2 levels [1].
• Moreover, overexpression of FAB1 suppresses the vac14-1 mutation, which suggests that VAC14 and FAB1 act at a common step [2].
• Consistent with these observations, we found that Fig4 physically associates with Vac14 in a common membrane-associated complex [3].
• Surprisingly, in the absence of Vac14, Fig4-GFP no longer localizes to the vacuole [3].
• Vac14 controls PtdIns(3,5)P(2) synthesis and Fab1-dependent protein trafficking to the multivesicular body [4].

Biological context of VAC14

• Vac14 contains motifs suggestive of a role in protein trafficking and interacts with several proteins involved in clathrin-mediated membrane sorting and phosphoinositide metabolism [4].

Anatomical context of VAC14

• Vac14 is essential for the regulated synthesis of PtdIns(3,5)P(2), for control of trafficking of some proteins to the vacuole lumen via the MVB, and for maintenance of vacuole size and acidity [4].

Other interactions of VAC14

• Like fab1 mutants, yeast lacking Vac14 have enlarged vacuoles that do not acidify correctly [4].
• CONCLUSIONS: Vac14 and Vac7 are both upstream activators of Fab1-catalysed PtdIns(3,5)P(2) synthesis, with Vac14 the dominant contributor to the hierarchy of control [4].

References