PDZD-8 and TEX-2 regulate endosomal PI(4,5)P homeostasis via lipid transport to promote embryogenesis in C. elegans.

Different types of cellular membranes have unique lipid compositions that are important for their functional identity. PI(4,5)P is enriched in the plasma membrane where it contributes to local activation of key cellular events, including actomyosin contraction and cytokinesis. However, how cells prevent PI(4,5)P from accumulating in intracellular membrane compartments, despite constant intermixing and exchange of lipid membranes, is poorly understood.

Molecular basis of accessible plasma membrane cholesterol recognition by the GRAM domain of GRAMD1b.

Cholesterol is essential for cell physiology. Transport of the "accessible" pool of cholesterol from the plasma membrane (PM) to the endoplasmic reticulum (ER) by ER-localized GRAMD1 proteins (GRAMD1a/1b/1c) contributes to cholesterol homeostasis. However, how cells detect accessible cholesterol within the PM remains unclear.