Articles of Significant Interest Selected from This Issue by the Editors
Abstract
<h2>Mathematical Modeling Can Help in Understanding Viral Entry</h2> To initiate infection, human immunodeficiency virus (HIV) spikes on the virion's surface engage the CD4 receptor on host cells. It is not known how many attachment contacts are required for productive infection. Magnus et al. (p. 1523-1531 ) use mathematical models to analyze the infectivity of genetically engineered HIV virions. In contrast to previous estimates, the authors find that the number of attachment contacts is larger than 1, ranging from 2 to 19. The mathematical modeling identifies key parameters that must be experimentally defined before the number of required spike-receptor interactions can be reliably estimated. Previous Section Next Section <h2>Baculovirus Reveals Dynamic Sorting of Proteins to the Nuclear Envelope</h2> Studies using envelope proteins of the occlusion-derived progeny of baculovirus have revealed a regulated pathway of protein transport to the inner nuclear membrane (INM). Braunagel et al. (p. 1280-1288 ) show that sorting factors are actively recruited to the endoplasmic reticulum (ER) membrane based on requirements of the protein in transit. The cellular sorting protein, importin-α-16, remains with the INM-directed protein at least through protein translocation across the pore membrane to the INM. Thus, sorting proteins can be actively recruited to