There is another homolog to KstR found in Mtb H37Rv (Rv3557c) that has previously been reported to also be involved in cholesterol metabolism, named KstR2 [38] . However, KstR is much more similar to the other members of the Mycobacterial tetR family discussed above than it is to KstR2. KstR2 is categorized into a separate orthogroup (orthogroup 32655) and is more distantly related to KstR.