Heat-Shock 70-Kd Protein 2

Alternative Names

  • HSPA2
  • Heat-Shock Protein, 70-KD, 2
  • HSP70-2
  • Heat-Shock Protein, 70-KD, 3
  • HSP70-3
Back to search Result
OMIM Number

140560

Gene Map Locus
14q24.1

Description

Heat shock proteins (HSPs) are one of the most abundant and evolutionarily conserved intracellular proteins and are induced under conditions of stress like heat, cold, or oxygen deprivation. These proteins are also known as molecular chaperonins, due to their role in facilitating other proteins in their proper folding, as well as in their intracellular transport.

HSPA2 is a member of the HSP70 family of proteins. Studies have indicated that this protein is necessary for the progression of meiosis in sperm cells, and thus plays a major role in spermatogenesis. More specifically, HSPA2 acts as a chaperonin for CDC2 (Cell Division Cycle 2, G1 to S and G2 to M), and is necessary for CDC2 and cyclin B1 to form a complex. This complex formation is further required for the activation of CDC2 , and the progression of the pachytene spermatocytes from the G2 to M phase of the meiotic cell cycle. In support of this role of HSPA2 in spermatogenesis, the HSPA2 gene was found to be down-regulated in sperm from infertile men with idiopathic oligoteratozoospermia.

Molecular Genetics

Like all other HSP70 proteins, HSPA2 contains an N-terminal ATPase domain, a substrate binding domain, and a C-terminal alpha helical domain. The gene coding for the protein is located on chromosome 14, and spans a length of 7.3 Kb. The protein itself, is about 640 amino acids long, and weighs 70 kDa. Expression studies have shown that as expected from its role, maximum expression of the protein takes place immediately after transcription in leptotene-zygotene spermatocytes. Incidentally, homologues of HSPA2 are present in the testes of many animals, indicating a conserved role of this protein across phyla.

Epidemiology in the Arab World

View Map

Other Reports

Tunisia

To investigate the susceptibility and prognostic implications of the genetic variation in TNF-a and HSP70-2 in breast carcinoma, Mestiri et al. (2001) conducted a case/control study with 243 unrelated Tunisian patients with breast carcinoma and 174 healthy control subjects and examined the associations of the clinicopathologic parameters and the genetic markers with the rates of the breast carcinoma specific overall survival (OVS) and the disease free survival (DFS). Mestiri et al. (2001) found an association between TNF2/TNF2 genotype and breast carcinoma. A high relative risk of breast carcinoma was found to be associated with one hsp70-2 homozygous genotype. The TNF2/TNF2 genotype showed a significant association with reduced DFS and OVS. Conversely, hspP2/P2 genotype is associated with increased OVS but not with DFS (P2 stands for the absence of a PstI site). Mestiri et al. (2001) indicated that genetic variation in HSP70-2 may represent not only markers for the increased risk of breast carcinoma but also may predict the clinical outcome.

Chouchane et al. (2001) designed a case-controlled study to investigate the potential association of stress protein (hsp70-2) and TNF-alpha gene polymorphisms with obesity. A polymerase chain reaction followed by digestion with the endonuclease Pst I was used to detect a polymorphic Pst I site at position 1267 of the Hsp70-2 gene in 343 unrelated Tunisian patients with obesity and 174 healthy control subjects. Results revealed highly significant differences in genotypic distribution of this bi-allelic locus compared to the control subject group. Homozygosity for one hsp70-2 allele was highly associated with obesity. Chouchane et al. (2001) concluded that Tunisian individuals carrying the P2/P2 genotype of the hsp70-2 gene may have an increased risk of obesity. Later, Jalbout et al. (2003) designed a case-controlled study to investigate the potential association of the genetic variation of the heat shock protein 70-2 (HSP70-2) with nasopharyngeal carcinoma (NPC) in Tunisians. They also investigated the association of the genetic variation of the tumor necrosis factor-alpha (TNF-alpha) with NPC in this study. A total of 140 Tunisian patients with primary NPC and 274 healthy control subjects were investigated in this study. The two allelic forms of HSP70-2, corresponding to the presence or the absence of the Pst I site, are referred to as HSP-P1 and HSP-P2, respectively. A significant relative risk of NPC was found associated with the HSP70-2 homozygous genotype (P2/P2; OR=2.309; P=0.006). Jalbout et al. (2003) suggested that the P2/P2 genotype of the Hsp70-2 gene may represent a genetic marker of increased risk of NPC in Tunisians.

Zouari Bouassida et al. (2004) conducted a study on 280 type 2 diabetes patients and 274 control subjects, all unrelated and Tunisian. Zouari Bouassida et al. (2004) suggested that the HSP polymorphism, namely the P2/P2 homozygous genotype, is associated with an increased risk of type 2 diabetes.

© CAGS 2024. All rights reserved.