Component of the EKC/KEOPS complex that is required for the formation of a threonylcarbamoyl group on adenosine at position 37 (t(6)A37) in tRNAs that read codons beginning with adenine. The complex is probably involved in the transfer of the threonylcarbamoyl moiety of threonylcarbamoyl-AMP (TC-AMP) to the N6 group of A37. PCC1 functions as a dimerization module for the complex. The EKC/KEOPS complex also promotes both telomere uncapping and telomere elongation. The complex is required for efficient recruitment of transcriptional coactivators. Component of the EKC/KEOPS complex composed of at least BUD32, CGI121, GON7, KAE1 and PCC1; the whole complex dimerizes. Belongs to the CTAG/PCC1 family.