Transporter Biology and Physiology - Michael F. Romero

Na+ Monocarboxylate Cotransporters, SMCT

These studies are carried out in collaboration with Dr. Sanford Markowitz HHMI & Ireland Cancer Center at Case

Last year, Dr. Hui Li in Dr. Sandy Markowitz's lab, discovered a novel tumor suppressor for colon cancer. When the promoter is methylated the gene is INactivated and results in colon cancer .... 100% of the time. Methylation mediated inactivation of this gene accounts for ~60% of all known colon cancers (Li et al., PNAS, 100: 8412-8417, 2003). This tumor suppressor gene is a transporter protein in the SLC5, aka, Na - glucose cotransporter family and was named SLC5A8. The SLC5A8 mRNA is found in kidney and colon.
Recently, in collaboration with Drs. Mike Coady and Jean-Yves Lapointe (U. Montreal), we discovered that SLC5A8 functions as a Na+ coupled monocarboxylate cotransporter (SMCT). We are continuing to work on the biophysics of SMCT to understand why its inactivation leads to colon cancer.