Description
FL cytokine receptor, also known as tyrosine-protein kinase receptor FLT3, Stem cell tyrosine kinase 1, STK-1, FLT3 and CD135, is a single-pass type I membrane protein. CD135 belongs to the protein kinase superfamily and the CSF-1/PDGF receptor subfamily. It contains one Ig-like C2-type domain and one protein kinase domain. CD135 is an important cell surface marker used to identify certain types of hematopoietic progenitors in the bone marrow. Specifically, multipotent progenitors (MPP) and common lymphoid progenitors (CLP) express surface CD135 at high levels. This marker is therefore used to differentiate hematopoietic stem cells (HSC), which are CD135 negative, from MPPs, which are CD135 positive. Signaling through CD135 plays a role in cell survival, proliferation, and differentiation. CD135 is also important for lymphocyte (B cell and T cell) development, but not for the development of other blood cells (myeloid development). Identified as a proto-oncogene, the mutations of FLTS gene are associated with certain carcinomas