OPHTHALMOLOGY: Growth Factor’s Protection of Eye Shows Dark Side of Anti-angiogenesis Drugs
A molecule better known for pathologic promotion of leaky new blood vessels in tumors and eye diseases also protects vision, according to a study of vascular endothelial growth factor (VEGF) in healthy adult mice. The study from the lab of Patricia D’Amore (right), including first author Magali Saint-Geniez, appears in the November PLoS One. If the findings hold true in people, they suggest a possible risk to anti-VEGF therapy and may warrant clinical precautions such as careful monitoring or a different follow-up regimen, with lower anti-VEGF doses in the meantime.

REGENERATIVE MEDICINE: Electrical Signaling Sparks Growth and Migration of Stem Cells
While the study of cellular signaling has predominantly focused on chemical signals, more and more research is showing that biophysical signals, such as bioelectricity, play roles in directing cells to proliferate, differentiate, and migrate. This is particularly true during development and regeneration. Now, research from Michael Levin (left), Junji Morokuma, and colleagues has uncovered a role for electrical signals in the control of embryonic stem cell multiplication and migration. Published in the Oct. 28 Proceedings of the National Academy of Sciences, the research demonstrates that bioelectrical signals in the microenvironment may regulate behaviors common to both stem and cancer cells. By identifying a bioelectric switch that triggers these behaviors, this work could lead to novel approaches to therapies that modulate them.

STRUCTURAL BIOLOGY: Blueprint Drawn for Molecular Transit Machine
Secretory and transmembrane proteins all face the challenge of getting across a lipid bilayer. In all kingdoms, their way is paved by a transmembrane channel, called the SecY complex in bacteria. But the mechanism that pushes the polypeptides through is largely a mystery. Recently, a team led by Tom Rapoport (right), with Jochen Zimmer (left) and Karl Erlandson, has solved a structure of the channel bound to a motor, SecA. The results give the researchers clues about how a polypeptide makes its way through; they further honed the model using biochemical techniques. Both of these studies are published in the Oct. 16 Nature. The SecA–SecY mechanism seems to share features with protein-degrading and unfolding enzymes, so this work may be useful for understanding a wide range of protein-handling processes.

Copyright 2008 by the President and Fellows of Harvard College