RNA chaperone that plays a key role in telomere maintenance and RNA localization to Cajal bodies (PubMed:29804836, PubMed:29695869). Specifically recognizes and binds the Cajal body box (CAB box) present in both small Cajal body RNAs (scaRNAs) and telomerase RNA template component (TERC) (PubMed:19285445, PubMed:20351177, PubMed:29804836, PubMed:29695869). Essential component of the telomerase holoenzyme complex, a ribonucleoprotein complex essential for the replication of chromosome termini that elongates telomeres in most eukaryotes (PubMed:19179534, PubMed:20351177, PubMed:26170453, PubMed:29695869). In the telomerase holoenzyme complex, required to stimulate the catalytic activity of the complex (PubMed:27525486, PubMed:29804836). Acts by specifically binding the CAB box of the TERC RNA and controlling the folding of the CR4/CR5 region of the TERC RNA, a critical step for telomerase activity (PubMed:29804836). In addition, also controls telomerase holoenzyme complex localization to Cajal body (PubMed:22547674). During S phase, required for delivery of TERC to telomeres during S phase and for telomerase activity (PubMed:29804836). In addition to its role in telomere maintenance, also required for Cajal body formation, probably by mediating localization of scaRNAs to Cajal bodies (PubMed:19285445, PubMed:21072240). Also plays a role in DNA repair: phosphorylated by ATM in response to DNA damage and relocalizes to sites of DNA double-strand breaks to promote the repair of DNA double-strand breaks (PubMed:25512560, PubMed:27715493). Acts by recruiting the ubiquitin ligase RNF8 to DNA breaks and promote both homologous recombination (HR) and non-homologous end joining (NHEJ) (PubMed:25512560, PubMed:27715493). Component of the telomerase holoenzyme complex composed of one molecule of TERT, one molecule of WRAP53/TCAB1, two molecules of H/ACA ribonucleoprotein complex subunits DKC1, NOP10, NHP2 and GAR1, and a telomerase RNA template component (TERC) (PubMed:19179534, PubMed:20351177, PubMed:26170453, PubMed:29695869). The telomerase holoenzyme complex is associated with TEP1, SMG6/EST1A and POT1 (PubMed:19179534). Interacts with the chaperonin-containing T-complex (TRiC) complex; which mediates the folding of WRAP53/TCAB1 (PubMed:25467444). Interacts with COIL (PubMed:21072240). Interacts with SMN1 (PubMed:21072240). Interacts with RNF8 (PubMed:25512560). Interacts with histone H2AX (PubMed:26734725, PubMed:27715493). Released from telomerase RNA template component (TERC) in mitotic cells coincident with delocalization from Cajal bodies (PubMed:26170453). In response to DNA damage, localizes to sites of DNA double-strand breaks following phosphorylation by ATM (PubMed:26734725, PubMed:27715493). Expressed in all tissues and cell lines examined. (Microbial infection) Over-expressed following infection by Epstein-Barr virus. Phosphorylated at Ser-64 by ATM in response to DNA damage, promoting its interaction with histone H2AX and localization to sites of DNA double-strand breaks. The disease is caused by variants affecting the gene represented in this entry. The mRNA encoding this protein plays a critical role in the regulation of p53/TP53 expression at the post-transcriptional level; it is involved both in maintaining basal p53/TP53 mRNA levels and in p53/TP53 induction upon DNA damage. Belongs to the TCAB1 family.