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Cell Microbiol. 2012 Aug;14(8):1299-317. doi: 10.1111/j.1462-5822.2012.01800.x. Epub 2012 May 14.

A novel class of cysteine protease receptors that mediate lysosomal transport.

Author information

1
Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan.

Abstract

The transport of lysosomal proteins is, in general, mediated by mannose 6-phosphate receptors via carbohydrate modifications. Here, we describe a novel class of receptors that regulate the transport of lysosomal hydrolases in the enteric protozoan Entamoeba histolytica, which is a good model organism to investigate membrane traffic. A novel 110 kDa cysteine protease (CP) receptor (CP-binding protein family 1, CPBF1) was initially discovered by affinity co-precipitation of the major CP (EhCP-A5), which plays a pivotal role in the pathogenesis of E. histolytica. We demonstrated that CPBF1 regulates EhCP-A5 transport from the endoplasmic reticulum to lysosomes and its binding to EhCP-A5 is independent of carbohydrate modifications. Repression of CPBF1 by gene silencing led to the accumulation of the unprocessed form of EhCP-A5 in the non-acidic compartment and the mis-secretion of EhCP-A5, suggesting that CPBF1 is involved in the trafficking and processing of EhCP-A5. The CPBF represents a new class of transporters that bind to lysosomal hydrolases in a carbohydrate-independent fashion and regulate their trafficking, processing and activation and, thus, regulate the physiology and pathogenesis of E. histolytica.

PMID:
22486861
PMCID:
PMC3465781
DOI:
10.1111/j.1462-5822.2012.01800.x
[Indexed for MEDLINE]
Free PMC Article

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