Certain short polycations, such as TAT and polyarginine, rapidly pass through cell plasma membranes by an unknown mechanism called transduction. These cell-penetrating peptides (CPPs)  when fused to biologically active peptides promise to be medically useful . I offer a simple model in which phosphatidylserines (and possibly other anions) transduce CPPs. The model is consistent with the empirical upper limit on the cargo peptide of about 35 amino acids. More importantly, the model fits experimental data on how the transduction of a polyarginine-fluorophore into mouse C2C12 myoblasts depends on the number of arginines in the CPP and on the CPP concentration  .
Certain short polycations, such as TAT and polyarginine, rapidly pass through the plasma membranes of mammalian cells by an unknown mechanism called transduction. These cell-penetrating peptides (CPPs) promise to be medically useful when fused to biologically active peptides . I offer a simple model in which phosphatidylserines transduce CPPs. The model is consistent with the empirical upper limit on the cargo peptide of about 50 amino acids. More importantly, it fits experimental data on how the transduction of a polyarginine-fluorophore into mouse C2C12 myoblasts depends on the number of arginines in the CPP and on the CPP concentration . The model makes two testable predictions .
R
cell plasma membranes
the plasma membranes of mammalian cells
A
promise to be medically useful
D
promise to be medically useful
D
(and possibly other anions)
R
35
50
R
the model
it
A
. The model makes two testable predictions