The TRP cation channel family consists of 6 mammalian subfamilies which comprise ~30 members. Endothelial cells express TRPV4, TRPM4, TRPP2 and several canonical TRPCs. We focus on the functional role of TRPV4 in mouse aorta endothelial cells, MAEC, from wild type TRPV4+/+ mice and from TRPV4 knockout mice TRPV4-/-. TRPV4 integrates a large variety of stimuli ranging from hypotonic cell swelling (HTS), shear stress, temperature, and α-phorbol ligands, to endogenous agonists such as arachidonic acid (AA) and epoxyeicosatrienoic acids. The binding site of the α-phorbol ligands have been identified as a complex binding pocket spanned by TM3 and TM4. TRPV4 is involved endothelium-dependent vasorelaxation, which can be modulated via the cytochrome P450 (CYP) pathway. The loss of TRPV4 in MAEC mice attenuated responses to all TRPV4 activating stimuli. TRPV4-dependent responses can be modulated via CYP enzymes, which metabolize AA to EETs. Upregulation of CYP2C expression by nifedipine in MAEC from TRPV4+/+ mice causes a potentiated response to AA and cell swelling. Sulfaphenazole, an inhibitor of CYP2C9, decreased responses induced by AA and HTS. 1-Adamantyl-3-cyclo-hexylurea (ACU), an inhibitor of the soluble epoxide hydrolase, which converts EETs to dihydroxyeicosatrienoic acids, increased the response induced by AA, HTS and EETs. All these data demonstrate that cytochrome P450-derived EETs modulate the activity of TRPV4 channels in endothelial cells.TRPV4-/- mice have a reduced flow-dependent vasorelaxation indicating that this channels my act as a mechano-sensor. As a model for mechano-sensing, we studied TRPV4 activation by cell swelling will be discussed in more detail. We show that N-terminal binding of Pacsin 3 to TRPV4 inhibits the mechano-activation by cell swelling. A possible mechanism and the underlying structural residues will be discussed.