Alternative splicing occurs at this locus and two transcript variants encoding distinct isoforms have been identified.

The longer gene product (isoform 1) enhances cell survival by inhibiting apoptosis while the alternatively spliced shorter gene product (isoform 2) promotes apoptosis and is death-inducing.

[8] Deletion of Mcl-1 in hepatocytes causes apoptosis and aberrant polyploidization but improves liver regeneration after surgery.

[8] Omacetaxine mepesuccinate (a drug approved for the treatment for chronic myelogenous leukemia) and Seliciclib[12] (which is under investigation as a potential multiple myeloma treatment) both act in part by inhibiting synthesis of Mcl-1.

MCL1 has been identified as a resistance factor for BCL-2 inhibitor venetoclax in lymphoma cells.