Updated publication reference for PubMed record(s): 29942010. CCAR1 mRNA have two transcripts, the 3.5 kb full length transcript and the 2.5 kb shorter transcript which contained a deletion in exon 15—exon 22 of full-length CCAR1 cDNA, where sequences mapped to 1196–3120 bp were missed. CCAR1L and CCAR1S shared a common N-terminus and a common C-terminal end, but the latter had a deletion of SAP domain. As a DNA/RNA-binding domain, the SAP motif is involved in chromosomal organization and apoptosis. To explaine the divergence of CCAR1L and CCAR1S in regulating apoptosis,we purified CCAR1L and CCAR1S from flag-CCAR1L or CCAR1S overexpressing A549 cells by performing IP-MS to screening the possible proteins which are specifically interacting with CCAR1L or CCAR1S.