In this article, we will explore the fascinating life of the famous PSIP1, whose contributions have left an indelible mark on history. From his humble beginnings to his rise to the top, PSIP1 has captivated people of all ages and from all walks of life. Throughout these pages, we will discover the achievements, challenges, and important moments that have defined PSIP1's journey, as well as his lasting impact on the world around him. Join us on this journey through the life of PSIP1 and discover how his legacy continues to inspire and influence generations to come.
PC4 and SFRS1 interacting protein 1, also known as lens epithelium-derived growth factor (LEDGF/p75), dense fine speckles 70kD protein (DFS 70) or transcriptional coactivator p75/p52, is a protein that in humans is encoded by the PSIP1gene.[5][6]
Function
PSIP1 has not been clearly linked to a specific cellular mechanism. The term LEDGF/p75 (Lens epithelium-derived growth factor) has entered common usage based on the initial characterization of PSIP1, however this is a misnomer, as the protein is present in most tissues and has no direct role in the development of lens epithelium. LEDGF/p75, a transcription coactivator, gained prominence as a host factor that assists HIV integration[7] and is probably the only integrase interactor whose knock-down severely affects the HIV integration levels.[8][9][10] The interaction between HIV integrase and human LEDGF/p75 is a promising target for anti-HIV drug discovery.[11] LEDGF/p75 recruits MLL complexes to HOX genes to regulate their expression.[12] LEDGF/p52 is shown to recruit splicing factors to H3K36 trimethylated chromatin to modulate alternative splicing,[13] also regulates HOTTIP lncRNA, which is shown to regulate HOX genes in cis.[14]
Structure
LEDGF/p75 is a 60kDa, 530-amino-acid-long protein.[15] The N-terminal portion of the protein consists of a PWWP domain, a nuclear localization sequence, and two copies of the AT-hook DNA binding motif. The C-terminal portion of LEDGF/p75 contains a structure termed the integrase-binding domain,[16] which interacts with lentiviral integrase proteins as well as numerous cellular proteins. The N-terminal portion interacts strongly with chromatin, making LEDGF/p75 a constitutively nuclear protein. An isoform of the protein, LEDGF/p52, is produced by alternative splicing. LEDGF/p52 shares the N-terminal 325 amino acids of LEDGF/p75 but lacks the integrase-binding domain.
^Singh DP, Kimura A, Chylack LT, Shinohara T (January 2000). "Lens epithelium-derived growth factor (LEDGF/p75) and p52 are derived from a single gene by alternative splicing". Gene. 242 (1–2): 265–73. doi:10.1016/S0378-1119(99)00506-5. PMID10721720.
^Christ F, Voet A, Marchand A, Nicolet S, Desimmie BA, Marchand D, Bardiot D, Van der Veken NJ, Van Remoortel B, Strelkov SV, De Maeyer M, Chaltin P, Debyser Z (June 2010). "Rational design of small-molecule inhibitors of the LEDGF/p75-integrase interaction and HIV replication". Nat. Chem. Biol. 6 (6): 442–8. doi:10.1038/nchembio.370. PMID20473303. S2CID37421436.
Van Maele B, Debyser Z (2005). "HIV-1 integration: an interplay between HIV-1 integrase, cellular and viral proteins". AIDS Rev. 7 (1): 26–43. PMID15875659.
Van Maele B, Busschots K, Vandekerckhove L, Christ F, Debyser Z (2006). "Cellular co-factors of HIV-1 integration". Trends Biochem. Sci. 31 (2): 98–105. doi:10.1016/j.tibs.2005.12.002. PMID16403635.
Singh DP, Ohguro N, Kikuchi T, Sueno T, Reddy VN, Yuge K, Chylack LT, Shinohara T (2000). "Lens epithelium-derived growth factor: effects on growth and survival of lens epithelial cells, keratinocytes, and fibroblasts". Biochem. Biophys. Res. Commun. 267 (1): 373–81. doi:10.1006/bbrc.1999.1979. PMID10623627.
Singh DP, Kimura A, Chylack LT, Shinohara T (2000). "Lens epithelium-derived growth factor (LEDGF/p75) and p52 are derived from a single gene by alternative splicing". Gene. 242 (1–2): 265–73. doi:10.1016/S0378-1119(99)00506-5. PMID10721720.
Kubo E, Fatma N, Sharma P, Shinohara T, Chylack LT, Akagi Y, Singh DP (2002). "Transactivation of involucrin, a marker of differentiation in keratinocytes, by lens epithelium-derived growth factor (LEDGF)". J. Mol. Biol. 320 (5): 1053–63. doi:10.1016/S0022-2836(02)00551-X. PMID12126624.
Ogawa Y, Sugiura K, Watanabe A, Kunimatsu M, Mishima M, Tomita Y, Muro Y (2004). "Autoantigenicity of DFS70 is restricted to the conformational epitope of C-terminal alpha-helical domain". J. Autoimmun. 23 (3): 221–31. doi:10.1016/j.jaut.2004.07.003. PMID15501393.
Okamoto M, Ogawa Y, Watanabe A, Sugiura K, Shimomura Y, Aoki N, Nagasaka T, Tomita Y, Muro Y (2004). "Autoantibodies to DFS70/LEDGF are increased in alopecia areata patients". J. Autoimmun. 23 (3): 257–66. doi:10.1016/j.jaut.2004.07.004. PMID15501396.