Retroviral replication requires the nuclear export and translation of unspliced, singly-spliced and multiply-spliced derivatives of the initial genomic transcript. Rec interacts with a highly structured RNA element (RcRE) present in the viral 3'LTR and recruits the cellular nuclear export machinery. This permits export to the cytoplasm of unspliced genomic or incompletely spliced subgenomic viral transcripts (By similarity). Forms homodimers, homotrimers, and homotetramers via a C-terminal domain. Associates with XPO1 and with ZNF145 (By similarity). Shuttles between the nucleus and the cytoplasm. When in the nucleus, resides in the nucleolus (By similarity). Despite functional similarity, Rec shares almost no sequence homology with HIV-1 Rev and HTLV-1 Rex. Has a type 2 genome. The HERV-K(HML-2) family contains type 1 and type 2 genomes depending on the absence or presence of 292 nucleotides at the 5'-end of the env gene. Rec proteins are translated from a doubly spliced transcript expressed exclusively by HERV-K(HML-2) type 2 proviral genomes. The first exon comprises the 87 N-terminal amino acids of the HERV-K(HMLM-2) type 2 envelope protein. The second exon (18 amino acids) is positioned in the 3' part of the proviral genome.