Human gene HSPA1B is an intron-less gene which encodes for the heat shock protein HSP70-2, a member of the Hsp70 family of proteins.[5] The gene is located in the major histocompatibility complex, on the short arm of chromosome 6, in a cluster with two paralogous genes, HSPA1A and HSPA1L.[6][7][8] HSPA1A and HSPA1B produce nearly identical proteins because the few differences in their DNA sequences are almost exclusively synonymous substitutions or in the three prime untranslated region, heat shock 70kDa protein 1A, from HSPA1A, and heat shock 70kDa protein 1B, from HSPA1B.[6] A third, more modified paralog to these genes exists in the same region, HSPA1L, which shares a 90% homology with the other two.[8]
Quick Facts Available structures, PDB ...
HSPA1B |
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PDB | Ortholog search: PDBe RCSB |
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List of PDB id codes |
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1HJO, 1S3X, 1XQS, 2E88, 2E8A, 2LMG, 3A8Y, 3ATU, 3ATV, 3AY9, 3D2E, 3D2F, 3JXU, 3LOF, 4IO8, 4J8F, 4PO2, 4WV5, 4WV7, 5AR0, 5AQZ, 3Q49,%%s3D2E |
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Identifiers |
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Aliases | HSPA1B, HSP70-1B, HSP70-2, HSP70.2, heat shock protein family A (Hsp70) member 1B, HSX70, HSPA1, HSP70-1, HSP72, HSP70.1 |
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External IDs | OMIM: 603012; MGI: 96244; HomoloGene: 74294; GeneCards: HSPA1B; OMA:HSPA1B - orthologs |
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Heat shock 70kDa protein 1B is a chaperone protein, cooperating with other heat shock proteins and chaperone systems to maintain proteostasis by stabilizing the structural conformation of other proteins in the cell and protecting against stress-induced aggregation.[9] Hsp70s have also been shown to bind and stabilize mRNA rich in adenine and uracil bases, independent of the occupational states of its other binding sites.[10] This protein is deactivated by binding ATP, and activated by its dephosphorylation to ADP, which requires a potassium ion to facilitate the hydrolysis, or ATP-ADP exchange.[11]
Hsp70-2 specifically is developmentally expressed in male germ line cells during meiosis, where it is necessary for the formation of the complex between CDC2 and cyclin B1.[12] It later becomes incorporated into the CatSper complex, a specialized calcium ion channel that enables spermatozoa motility.[13]
Infertility has been observed in mice when HSA1B expression is disrupted, as CDC2 in unable to form the required heterodimer with cyclin B1 for the meiotic cell cycle to progress beyond S phase.[12]
Expression of heat shock protein 70kDa protein 2 in transformed tumor cells has been implicated in the rapid proliferation, metastasis, and inhibition of apoptosis in ovarian, bladder urothelial, and breast cancers.[14][15][16] Patients with chronic hepatitis B or hepatitis C virus infection who harbor a HSPA1B-1267 single nucleotide polymorphism have a higher risk for developing hepatocellular carcinoma.[17]
Interactions have been characterized between Hsp70-2 and the following proteins:
- ATF5,[18]
- BAG1,[19]
- BAG2,[19]
- BAG3,[19]
- CatSperβ,[13]
- CDC2,[20]
- CHCHD3,[21]
- DNAJC7,[22][23]
- DNAJC8,[24]
- DNAJC9,[25][26]
- FOXP3,[27]
- HDAC4,[28]
- HOPX,[28]
- HSP40,[28]
- HSP90,[28]
- HSP105,[19]
- IRAK1BP1,[29]
- METTL21A,[30]
- NAA10,[28]
- NEDD1,[31]
- NOD2,[32]
- PPP5C,[33]
- PKRN,[34]
- SMAD3,[35]
- STUB1,[28]
- TERT,[36]
- TRIM5,[37]
- TSC2,[38]
Ito Y, Ando A, Ando H, Ando J, Saijoh Y, Inoko H, Fujimoto H (August 1998). "Genomic structure of the spermatid-specific hsp70 homolog gene located in the class III region of the major histocompatibility complex of mouse and man". Journal of Biochemistry. 124 (2): 347–353. doi:10.1093/oxfordjournals.jbchem.a022118. PMID 9685725.
Garg M, Kanojia D, Seth A, Kumar R, Gupta A, Surolia A, Suri A (January 2010). "Heat-shock protein 70-2 (HSP70-2) expression in bladder urothelial carcinoma is associated with tumour progression and promotes migration and invasion". European Journal of Cancer. 46 (1): 207–215. doi:10.1016/j.ejca.2009.10.020. PMID 19914824.
Moffatt NS, Bruinsma E, Uhl C, Obermann WM, Toft D (August 2008). "Role of the cochaperone Tpr2 in Hsp90 chaperoning". Biochemistry. 47 (31): 8203–8213. doi:10.1021/bi800770g. PMID 18620420.
Ito N, Kamiguchi K, Nakanishi K, Sokolovskya A, Hirohashi Y, Tamura Y, et al. (June 2016). "A novel nuclear DnaJ protein, DNAJC8, can suppress the formation of spinocerebellar ataxia 3 polyglutamine aggregation in a J-domain independent manner". Biochemical and Biophysical Research Communications. 474 (4): 626–633. doi:10.1016/j.bbrc.2016.03.152. PMID 27133716.
Han C, Chen T, Li N, Yang M, Wan T, Cao X (February 2007). "HDJC9, a novel human type C DnaJ/HSP40 member interacts with and cochaperones HSP70 through the J domain". Biochemical and Biophysical Research Communications. 353 (2): 280–285. doi:10.1016/j.bbrc.2006.12.013. PMID 17182002.
Haag Breese E, Uversky VN, Georgiadis MM, Harrington MA (December 2006). "The disordered amino-terminus of SIMPL interacts with members of the 70-kDa heat-shock protein family". DNA and Cell Biology. 25 (12): 704–714. doi:10.1089/dna.2006.25.704. PMID 17233114.
Shang Y, Xu X, Duan X, Guo J, Wang Y, Ren F, et al. (March 2014). "Hsp70 and Hsp90 oppositely regulate TGF-β signaling through CHIP/Stub1". Biochemical and Biophysical Research Communications. 446 (1): 387–392. doi:10.1016/j.bbrc.2014.02.124. PMID 24613385.
Nellist M, Burgers PC, van den Ouweland AM, Halley DJ, Luider TM (August 2005). "Phosphorylation and binding partner analysis of the TSC1-TSC2 complex". Biochemical and Biophysical Research Communications. 333 (3): 818–826. doi:10.1016/j.bbrc.2005.05.175. PMID 15963462.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.