A novel TGFbeta Inducible Early Gene-1 (TIEG1) was discovered in human 
osteoblast (OB) cells by our laboratory. Over the past decade, a handful of 
laboratories have revealed a multitude of organismic, cellular, and molecular 
functions of this gene. TIEG1 is now classified as a member of the 3 zinc finger 
family of Krüppel-like transcription factors (KLF10). Other closely related 
factors [TIEG2 (KLF11) and TIEG3/TIEG2b] have been reported and are briefly 
compared. As described in this review, TIEG1 is shown to play a role in 
regulating estrogen and TGFbeta actions, the latter through the Smad signaling 
pathway. In both cases, TIEG1 acts as an inducer or repressor of gene 
transcription to enhance the TGFbeta/Smad pathway, as well at other signaling 
pathways, to regulate cell proliferation, differentiation, and apoptosis. This 
review outlines TIEG1's molecular functions and roles in skeletal disease 
(osteopenia/osteoporosis), heart disease (hypertrophic cardiomyopathy), and 
cancer (breast and prostate).