Tribbles homolog 2, also known as TRB-2, and Trib2, is a member of the protein kinase superfamily and Tribbles subfamily (Trib1, Trib2, Trib3). The identification of tribbles as regulators of signal processing systems and physiological processes, including development, together with their potential involvement in diabetes and cancer, has generated considerable interest in these proteins. Tribbles have been reported to regulate the activation of some intracellular signalling pathways with roles extending from mitosis and cell activation to apoptosis and modulation of gene expression. Tribbles control the timing of mitosis in the prospective mesoderm, allowing cell-shape changes to be completed. This mechanism for coordinating cell division and cell-shape changes may have helped Drosophila to evolve its mode of rapid early development. Trib2 was identified as a downregulated transcript in leukemic cells undergoing growth arrest. Trib2-transduced bone marrow cells exhibited a growth advantage and readily established factor-dependent cell lines. Trib2-reconstituted mice uniformly developed fatal transplantable acute myelogenous leukemia (AML).