This is a region of 130 amino acids that is the most conserved region of hypothetical proteins involved in loss of heterozygosity and thus tumour suppression [1]. The exact function of family members is not known. This region is also found in subunit 5 of the BLOC-1-related complex, which is also found in the BORC complex. BLOC-1 is important for the biogenesis of lysosome-related organelles, and BORC is important for the positioning of the lysosome in the cytoplasm. The BORC complex associates with the lysosomal membrane where it recruits the small GTPase Arl8, which leads in turn to the kinesin-dependent movement of lysosomes toward the plus ends of microtubules in the peripheral cytoplasm [2].

1: A detailed transcriptional map of the chromosome 12p12 tumour suppressor locus. Montpetit A, Boily G, Sinnett D; Eur J Hum Genet. 2002;10:62-71. PMID:11896457

2: BORC, a multisubunit complex that regulates lysosome positioning. Pu J, Schindler C, Jia R, Jarnik M, Backlund P, Bonifacino JS; Dev Cell. 2015;33:176-188. PMID:25898167