HM13 and cancer: In addition, other Elk-1-interacting proteins include CPT1A, carnitine O-palmitoyltransferase, a mitochondrial membrane enzyme and plays a role in fatty acid oxidation, which is known to promoter metastasis and proliferation in cancer cells [33]; HM13, which catalyzes proteolysis of signal peptides in the ER and was found to contribute to tumor progression [34, 35]; and choline/ethanolamine phosphotransferase CEPT1, which is involved in the synthesis of choline-containing phospholipids, which is reported to be upregulated in certain types of cancer [36].