This entry includes caltractin (a calcium-binding protein found in the basal body complexes of algae such as Chlamydomonas) and centrin-2. Centrin-2 (CETN2, also known as caltractin isoform 1) is important for microtubule organization, centriole duplication and correct spindle formation. It is a calcium-binding protein with EF-hand binding sites []. It is a component of the XPC (xeroderma pigmentosum group C) and TREX-2 ((transcription and export complex 2)) complexes. The XPC complex recognizes damaged DNA which is required for global genome nucleotide excision repair []. Once XPC has interacted with unpaired bases on the undamaged DNA strand, the TFIH complex is recruited to find lesions on the opposite strand. The XPC complex is composed of XPC, RAD23B and CETN2 []. The TREX-2 complex helps dock export-competent ribonucleoprotein particles to the nuclear entrance of the nuclear pore complex []. The TREX-2 complex consists of at least ENY2, GANP, PCID2, SEM1, and either centrin CETN2 or CETN3 [].
