The 26Sproteasome is a multicatalyticproteinase complex with a highly ordered structure composed of 2 complexes, a 20S core and a 19S regulator. The 20S core is composed of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. The 19S regulator is composed of a base, which contains 6ATPase subunits and 2 non-ATPase subunits, and a lid, which contains up to 10 non-ATPase subunits. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in anATP/ubiquitin-dependent process in a non-lysosomal pathway. An essential function of a modified proteasome, the immunoproteasome, is the processing of class IMHC peptides. PSMF1 encodes a protein termed PI31 that binds to both 20S and 26S proteasomes. PI31 was originally identified by its ability to inhibit the hydrolysis of small synthetic peptides in a cell free assay, but it stimulates 26S proteasome activity both in vitro and in vivo.[7][8] PI31 can promote the assembly of 26S proteasomes from 19S and 20S sub-particles, and it also serves as an adapter to couple proteasomes with motor proteins to mediate fast axonal transport in neurons.[9] Inactivation of PMSF1 in yeast, plants, fruit flies and mice attenuates protein degradation and stimulates accumulation of ubiquitinated protein aggregates. Furthermore, loss of PSMF1 function in mice causes progressive neuronal dysfunction, synaptic degeneration and eventually neuronal cell death.[10] Alternative transcript variants have been identified for this gene.[6]
^Chu-Ping, M (1992). "Purification and characterization of a protein inhibitor of the 20S proteasome (macropain)".Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology.1119 (3):303–11.doi:10.1016/0167-4838(92)90218-3.PMID1312359.
Minghetti L, Visentin S, Patrizio M, Franchini L, Ajmone-Cat MA, Levi G (May 2004). "Multiple actions of the human immunodeficiency virus type-1 Tat protein on microglial cell functions".Neurochemical Research.29 (5):965–78.doi:10.1023/B:NERE.0000021241.90133.89.PMID15139295.S2CID25323034.
Liou LY, Herrmann CH, Rice AP (Sep 2004). "HIV-1 infection and regulation of Tat function in macrophages".The International Journal of Biochemistry & Cell Biology.36 (9):1767–75.doi:10.1016/j.biocel.2004.02.018.PMID15183343.
Bannwarth S, Gatignol A (Jan 2005). "HIV-1 TAR RNA: the target of molecular interactions between the virus and its host".Current HIV Research.3 (1):61–71.doi:10.2174/1570162052772924.PMID15638724.
Gibellini D, Vitone F, Schiavone P, Re MC (Apr 2005). "HIV-1 tat protein and cell proliferation and survival: a brief review".The New Microbiologica.28 (2):95–109.PMID16035254.
Simon JH, Gaddis NC, Fouchier RA, Malim MH (Dec 1998). "Evidence for a newly discovered cellular anti-HIV-1 phenotype".Nature Medicine.4 (12):1397–400.doi:10.1038/3987.PMID9846577.S2CID25235070.
Huang X, Seifert U, Salzmann U, Henklein P, Preissner R, Henke W, Sijts AJ, Kloetzel PM, Dubiel W (Nov 2002). "The RTP site shared by the HIV-1 Tat protein and the 11S regulator subunit alpha is crucial for their effects on proteasome function including antigen processing".Journal of Molecular Biology.323 (4):771–82.doi:10.1016/S0022-2836(02)00998-1.PMID12419264.
