The organization, structure, and inheritance of the ER in higher and lower eukaryotes

The endoplasmic reticulum (ER) is a fundamental organelle required for protein assembly, lipid biosynthesis, and vesicular traffic (McMaster 2001; Staehelin 1997; Voeltz et al. 2002), as well as calcium storage and the controlled release of calcium from the ER lumen into the cytosol (Johnson and van Waes 1999; Ma and Hendershot 2002; Matlack et al. 1998; Meldolesi and Pozzan 1998). Membranes functionally linked to the ER by vesicle-mediated transport, such as the Golgi complex, endosomes, vacuoles-lysosomes, secretory vesicles, and the plasma membrane, originate largely from proteins and lipids synthesized in the ER (Voeltz et al. 2002). In this review we will discuss the structural organization of the ER and its inheritance.