Principal Names: Activator of CREM in Testis; (FHL5) Four and half LIM domains 5; 1700027G07Rik; dJ393D12.2, FLJ33049 Official Gene Symbol: FHL5 Gene ID: 9457 (Human) Gene Map Locus: 6p16.1-1p16.3 (Human)
FHL proteins are tissue specific cofactors of CREB and CREM and participate in regulation of various physiological processes. These proteins are characterized by the presence of 4 LIM domains and a LIM-half domain at the N-terminus. ACT, a 33KDa protein, is a novel member of this family. It is specifically expressed in male testis and consists of a central activation domain. It is coordinately expressed with CREM and plays a vital role in spermatogenesis. It binds specifically to CREM and powerfully stimulates its transcriptional activation, essential for differentiation of spermatids into mature spermatozoa. It activates CREM in a phosphorylation- and CBP-independent manner. Protein-protein interactions with a Kinesin KIF17B regulate ACT activity in mouse.