Leucine Rich Repeat Containing Protein 4 (LRRC4)

LRRC4 is significantly downregulated in primary brain tumors. The deduced 653-amino acid LRRC4 protein has an N-terminal signal sequence, followed by a leucine-rich repeat (LRR) region, a C2-type immunoglobulin (Ig)-like domain, and a C-terminal transmembrane region.

The LRR region consists of a tandem array of 9 and a half LRRs flanked by conserved cysteine-rich clusters on its N- and C-terminal ends. Northern blot analysis detected a 3.9-kb LRRC4 transcript in brain, but not in 15 other tissues examined. Examination of specific brain regions revealed highest LRRC4 expression in cerebellum, followed by occipital pole, frontal and temporal lobes, cerebral cortex, and putamen; no expression was detected in medulla or spinal cord.