title: Characterization of the adaptor protein ARH expression in the brain and ARH molecular interactions.
abstract: Previously, pA134 was identified as one of the mRNAs present in the squid giant axon. Comparative sequence analyses revealed that the pA134 gene product manifested significant similarity to the mammalian lipoprotein receptor adaptor protein also known as ARH (autosomal recessive hypercholesterolemia). ARH mRNA and protein displayed very similar pattern of expression throughout the mouse brain. Significant levels of expression were observed in cells with a predominantly neuronal profile in the cerebellum, brainstem, olfactory bulb, hippocampus, and cortex. A yeast two hybrid screen for ARH protein interactions in mouse brain identified the following binders: amyloid precursor-like protein 1, low density lipoprotein receptor-related protein (LRP) 1, LRP8, and GABA receptor-associated protein-like 1. The interactions of ARH with LRP1 and GABA receptor-associated protein-like 1 were subsequently verified by co-immunoprecipitation of the protein complexes from transfected human embryonic kidney cells. The presence of ARH mRNA in axon of primary sympathetic neurons was established by RT-PCR analyses and confirmed by in situ hybridization. Taken together, our data suggest that ARH is a multifunctional protein whose spectrum of function in the brain goes beyond the traditionally known metabolism of lipoproteins, and that ARH may be locally synthesized in the axon.
authors.affiliation: Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Marie Germaine
authors.initials: MG
authors.lastname: Mameza
authors.forename: Jon M
authors.initials: JM
authors.lastname: Lockard
authors.forename: Eduardo
authors.initials: E
authors.lastname: Zamora
authors.forename: Mi
authors.initials: M
authors.lastname: Hillefors
authors.forename: Zeno Scotto
authors.initials: ZS
authors.lastname: Lavina
authors.forename: Barry B
authors.initials: BB
authors.lastname: Kaplan
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D001923:Brain Chemistry / Q000502:physiology*; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000378:metabolism; D049832:Decapodiformes / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005728:Ganglia, Sympathetic / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D008074:Lipoproteins / Q000378:metabolism*; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008869:Microtubule-Associated Proteins; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011973:Receptors, LDL / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D003598:Cytoskeletal Proteins; C480861:GABARAP protein, mouse; C500241:Ldlrap1 protein, mouse; D008074:Lipoproteins; D026503:Low Density Lipoprotein Receptor-Related Protein-1; C486645:Lrp1 protein, mouse; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D011973:Receptors, LDL; D025521:Tumor Suppressor Proteins