Sra Stem Loop Interacting RNA Binding Protein (SLIRP)

The deduced 109-amino acid protein contains a putative N-terminal mitochondrial localization sequence and a central RNA recognition domain with RNP1 and RNP2 submotifs. It has putative sites for N-myristoylation and phosphorylation. Northern blot analysis detected variable expression of SLIRP in all tissues examined, with highest levels in heart, liver, skeletal muscle, and testis. Western blot analysis detected SLIRP at an apparent molecular mass of 12.7 kD in several human cell lines. Immunohistochemical analysis of primary breast cancer tissue showed high SLIRP expression in a punctate cytoplasmic distribution. Expression was lower in normal ductal tissue, and no expression was detected in the surrounding stroma. SLIRP colocalized with a mitochondrial marker protein.