Posttranslational modifications of CENP-A and CCAN recruitment. (a) A schematic of CENP-A secondary structure showing the locations of posttranslational modifications. Note that Ser16, Ser18 and Gly1 are numbered based on the removal of the initiating methionine, in convention with other histone proteins; however, these modifications have also been referred to by Ser17, Ser19 and Gly2, respectively. (b) Centromeric histone H4 and CENP-A posttranslational modifications found in centromeric chromatin. CCAN proteins (CENP-H/I/K/M, CENP-T/W/S/X and CENP-C) whose localization are influenced by CENP-A modifications are colored. (c) Location of phosphorylated Ser68 and modified Lys124 (green) within the CENP-A nucleosome (left) and the CENP-A/H4/HJURPScm3 pre-nucleosomal complex (right). Based on crystal structures, 3AN2 (human CENP-A nucleosome) and 3R45 (human CENP-A and histone H4 heterodimer bound to HJURP amino acids 1–80).