Plastins are a family of actin-binding proteins that are
conserved throughout eukaryote evolution and expressed in most
tissues of higher eukaryotes. In humans, two ubiquitous plastin
isoforms (L and T) have been identified. Plastin 1 (otherwise known
as Fimbrin) is a third distinct plastin isoform which is
specifically expressed at high levels in the small intestine. The L
isoform is expressed only in hemopoietic cell lineages, while the T
isoform has been found in all other normal cells of solid tissues
that have replicative potential (fibroblasts, endothelial cells,
epithelial cells, melanocytes, etc.). However, L-plastin has been
found in many types of malignant human cells of non-hemopoietic
origin suggesting that its expression is induced accompanying
tumorigenesis in solid tissues.
