Primary Sertoli Cell Cultures From Adult Mice Have Different Properties Compared With Those Derived From 20-Day-Old Animals.

Cultures of Sertoli cells isolated from 20-day-old mice are widely used in research as substitutes for adult Sertoli cell cultures. This practice is based on the fact that Sertoli cells cease to proliferate and become mature in vivo by 16 to 20 days after birth. However, it is important to verify whether cultured Sertoli cells derived from 20-day-old mice do not proliferate ex vivo and whether they have the same properties as cultured adult Sertoli cells.

Clusterin in the mouse epididymis: possible roles in sperm maturation and capacitation.

Clusterin (CLU) is known as an extracellular chaperone for proteins under stress, thus preventing them from aggregation and precipitation. We showed herein that CLU, expressed by principal cells of the mouse caput epididymis, was present in high amounts in the lumen. In the cauda epididymis, CLU bound tightly to the sperm head surface and its amount on total sperm was similar to that in the bathing luminal fluid.

mTOR complex 1 activity is required to maintain the canonical endocytic recycling pathway against lysosomal delivery.

The plasma membrane of mammalian cells undergoes constitutive endocytosis, endocytic sorting, and recycling, which delivers nutrients to the lysosomes. The receptors, along with membrane lipids, are normally returned to the plasma membrane to sustain this action. It is not known, however, whether this process is influenced by metabolic conditions.

Transbilayer lipid interactions mediate nanoclustering of lipid-anchored proteins.

Understanding how functional lipid domains in live cell membranes are generated has posed a challenge. Here, we show that transbilayer interactions are necessary for the generation of cholesterol-dependent nanoclusters of GPI-anchored proteins mediated by membrane-adjacent dynamic actin filaments. We find that long saturated acyl-chains are required for forming GPI-anchor nanoclusters.

Homo-FRET imaging highlights the nanoscale organization of cell surface molecules.

Several models have been proposed to understand the structure and organization of the plasma membrane in living cells. Predicated on equilibrium thermodynamic principles, the fluid-mosaic model of Singer and Nicholson and the model of lipid domains (or membrane rafts) are dominant models, which account for a fluid bilayer and functional lateral heterogeneity of membrane components, respectively. However, the constituents of the membrane and its composition are not maintained by equilibrium mechanisms.

Synthesis of non-hydrolysable mimics of glycosylphosphatidylinositol (GPI) anchors.

Synthesis of first generation non-hydrolysable C-phosphonate GPI analogs, viz., 6-O-(2-amino-2-deoxy-α-d-glucopyranosyl)-d-myo-inositol-1-O-(sn-3,4-bis(palmitoyloxy)butyl-1-phosphonate) and 6-O-(2-amino-2-deoxy-α-d-glucopyranosyl)-d-myo-inositol-1-O-(sn-2,3-bis(palmitoyloxy)propyl-1-phosphonate) 23b, is reported. The target compounds were synthesized by the coupling of α-pseudodisaccharide 21 with phosphonic acids 18a and 18b respectively in quantitative yield followed by de-protection.

Nanoclusters of GPI-anchored proteins are formed by cortical actin-driven activity.

Several cell-surface lipid-tethered proteins exhibit a concentration-independent, cholesterol-sensitive organization of nanoscale clusters and monomers. To understand the mechanism of formation of these clusters, we investigate the spatial distribution and steady-state dynamics of fluorescently tagged GPI-anchored protein nanoclusters using high-spatial and temporal resolution FRET microscopy. These studies reveal a nonrandom spatial distribution of nanoclusters, concentrated in optically resolvable domains.