||November 21, 2008
Growth Factor’s Protection of Eye Shows Dark Side of Anti-angiogenesis
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.
Electrical Signaling Sparks Growth and Migration of Stem Cells
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.
Blueprint Drawn for Molecular
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