High impact information on HPS6

• HPS results from mutations in either one of six human genes named HPS1 to HPS6, most of which encode proteins of unknown function [1].
• Here, we report the biochemical characterization of a stable protein complex named Biogenesis of Lysosome-related Organelles Complex-2 (BLOC-2), which contains the HPS3, HPS5 and HPS6 proteins as subunits [2].
• Fibroblasts deficient in the BLOC-2 subunits HPS3 or HPS6 displayed normal basal secretion of the lysosomal enzyme beta-hexosaminidase [2].
• As inferred from the biochemical properties of the HPS6 subunit, BLOC-2 exists in a soluble pool and associates to membranes as a peripheral membrane protein [2].
• Most frameshift mutations generating premature termination codon cause mRNA nonsense mediated decay (NMD), while intronless genes like HPS6 are usually not monitored by NMD [3].

Biological context of HPS6

• The HPS-6 phenotype in the studied family is unique since it resembles OCA and not HPS [3].

Anatomical context of HPS6

• The endogenous HPS3, HPS5 and HPS6 proteins from human HeLa cells coimmunoprecipitated with each other from crude extracts as well as from fractions resulting from size-exclusion chromatography and density gradient centrifugation [2].

Other interactions of HPS6

• So far, a single HPS-6 patient phenotypically similar to HPS-3 and HPS-5 has been identified [3].

References