Soluble fms-like tyrosine kinase-1

Soluble fms-like tyrosine kinase-1 (sFlt-1 or sVEGFR-1), a tyrosine kinase protein which disables proteins that cause blood vessel growth.

Splicing of the Flt-1 pre m-RNA can result in the full-length Flt-1 receptor, or in its shorter soluble form: sFlt-1. These proteins act as a receptor of vascular endothelial growth factor (VEGF), a potent angiogenic growth factor. (Another VEGF receptor is KDR).

Soluble Flt-1 binds and inhibits VEGF activity,- a VEGF antagonist. It is also an antagonist of placental growth factor, PlGF. Like soluble endoglin, it has been found to be implicated in the development of pre-eclampsia.

The activity of this enzyme is responsible for the non-vascular nature of the cornea of the eye of most mammals. In the manatee, which has a vascular cornea, this kinase is not active.