Protein transduction has been demonstrated to be an effective way of intracellular delivery of recombinant proteins or small peptides. The most intensely studied transduction peptide is the protein transduction domain (PTD) of the HIV transcription factor TAT. Protein transduction technique presents certain advantages over transfection techniques. For instance, it allows control of the expression levels and induction time, circumventing the problems of transfection and gene overexpression. Since it is independent of membrane receptors it can be used over all types of cells. We have taken advantage of the transduction technique to study aqueous humor outflow and intraocular pressure regulation. By means of an a recombinant protein fusing Profilin I, an actin binding protein, to a protein transduction domain of the TAT family (PTD4-PfnI), we studied the role of trabecular meshwork actin cytoskeleton modulating the passage of AH through this tissue. When added to primary trabecular meshwork cells in culture, PTD4-PfnI rapidly crossed cell membrane to induce an extensive lamellipodia formation and increase cell spreading velocity. In bovine perfused anterior segments, PTD4-PfnI raised trabecular outflow facility. Additionally, when topically applied to the cornea, PTD4-PfnI, was able to reduced the intraocular pressure in rabbits. Our results indicate that regulation of actin cytoskeleton by Profilin I may be an important modulator of AH outflow and intraocular pressure. Moreover, our results prove the applicability of protein transduction technology to TM tissue, being an interesting tool to study its physiology and a possible drug-delivery method.