PS - is Phosphatidylserine

what is it?
a phospholipid, which are the principal components of all cell membranes.

what does it do?
PS provides for five special benefits:

It activates cell-to-cell communication;
It stabilizes the inner environment of the cell;
It helps regulate cell growth;
It improves the functioning of the special recepters found on cells, and it prepares cells for activity.
PS is most concentrated in the cells of the brain. PS promotes the stability and integrity of the cellular membrane and promotes the ability of cells to maintain the internal balance known as homeostasis.

I googled it for you all.
and tiny url'd it as well -
link for study

http://tinyurl.com/28jchw

also mamma search engine is great - goes into the deep web...

http://www.jcb.org/cgi/reprint/155/4/649

Phosphatidylserine (PS) induces
PS receptor–mediated macropinocytosis
and promotes clearance of apoptotic cells
Peter R. Hoffmann,
1
Aimee M. deCathelineau,
1
Carol Anne Ogden,
1
Yann Leverrier,
2
Donna L. Bratton,
1
David L. Daleke,
3
Anne J. Ridley,
2
Valerie A. Fadok,
1
and Peter M. Henson
1
1
Program in Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO 80206
2
Ludwig Institute for Cancer Research, London W1P 8BT, UK
3
Department of Biochemistry and Molecular Biology/Medical Sciences, Indiana University, Bloomington, IN 47405
fficient phagocytosis of apoptotic cells is important for
normal tissue development, homeostasis, and the
resolution of inflammation. Although many receptors
have been implicated in the clearance of apoptotic cells,
the roles of these receptors in the engulfment process have
not been well defined. We developed a novel system to
distinguish between receptors involved in tethering of
apoptotic cells versus those inducing their uptake. Our
results suggest that regardless of the receptors engaged on