Ring Finger And KH Domain Containing Protein 2 (RKHD2)

The deduced protein contains a RING-type zinc finger domain and a ribonucleoprotein K (HNRNPK) homology (KH) domain. Microarray data showed that RKHD2 was expressed in most tissues and cell lines analyzed.Like the other human MEX3 proteins, the deduced 659-amino acid MEX3C protein has an N-terminal nuclear export signal (NES), 2 KH domains, and a C-terminal RING finger domain. The KH domains are present in C. elegans Mex3, but not the RING domain. MEX3C also has a C-terminal nuclear localization signal. RT-PCR detected variable expression of MEX3C in human tissues and cell lines, with highest expression in testis.Immunofluorescence analysis of transfected breast cancer cells showed that MEX3A, MEX3B, and MEX3C shuttled between the nucleus and cytoplasm in an NES-dependent manner.