sentences:  The protein was first identified by its reactivity with monoclonal antibody K1.Subsequent cloning studies showed that the mesothelin gene encodes a precursor protein that is processed to yield mesothelin which is attached to the cell membrane by a glycophosphatidylinositol linkage and a 31-kDa shed fragment named megakaryocyte-potentiating factor (MPF).Although it has been proposed that mesothelin may be involved in cell adhesion, its biological function is not known.