Heat shock protein X (alpha-crystallin homolog) (HspX)

Heat shock protein X (HspX), also known as alpha-crystallin homolog or Rv2031c, is a small heat shock protein (about 16 kDa) from Mycobacterium tuberculosis critical for bacterial survival under hypoxic (low oxygen) and latent states[1][5][6]. HspX acts as a molecular chaperone, maintaining protein folding and preventing aggregation during stress[1][3][6]. It is highly induced in hypoxic conditions regulated by the DosR regulon, localized in various cellular compartments (including membrane and cytosol)[6], and is an immunodominant antigen recognized by tuberculosis patient sera, making it a key biomarker and vaccine target[2][4][6]. Deletion or overexpression in M. tuberculosis affects bacterial growth dynamics and persistence, demonstrating its regulatory role in the latent phase[1][5].

Other names

16 kDa antigen14 kDa antigenHSP 16.3alpha-crystallinacrRv2031c

Antigen for vaccine development (stimulates immune response); Induction of both humoral and cell-mediated immunity (as vaccine antigen)[4].