3 Immunodominant epitopes of CENP-A
CENP-A, like other CENPs, belongs to the kinetochore, a centromeric protein complex
essential for mitosis [100] and thus is localized at all active centromeres [99,113]. This 17-kDa
protein is a minor nuclear component, representing 0.025% of all chromatin proteins in HeLa
cells [112]. It is homologous to histone H3 in its central and carboxyl terminal portions, but its
amino terminal portion (residues 1 to 45) is unique [112,114]. In 2006, Akbarali et al. [115]
described two immunodominant epitopes of CENP-A, identified by peptide scanning analysis of
sera from SSc patients with anti-CENP-A antibodies. These epitopes were localized to the amino
terminus: peptide Ap1–17 spanned residues 1 to 17 (MGPRRRSRKPEAPRRRS), while peptide
Ap17–30 corresponded to residues 17 to 30 (SPSPTPTPGPSRRG).