TY - JOUR
T1 - Both sphingomyelin synthases SMS1 and SMS2 are required for sphingomyelin homeostasis and growth in human HeLa cells
AU - Tafesse, Fikadu Geta
AU - Huitema, Klazien
AU - Hermansson, Martin
AU - Poel, Selene van der
AU - Dikkenberg, Joep van den
AU - Uphoff, Andreas
AU - Somerharju, Pentti
AU - Holthuis, Joost
PY - 2007
Y1 - 2007
N2 - Sphingomyelin ( SM) is a vital component of cellular membranes in organisms ranging from mammals to protozoa. Its production involves the transfer of phosphocholine from phosphatidylcholine to ceramide, yielding diacylglycerol in the process. The mammalian genome encodes two known SM synthase ( SMS) isoforms, SMS1 and SMS2. However, the relative contributions of these enzymes to SM production in mammalian cells remained to be established. Here we show that SMS1 and SMS2 are co-expressed in a variety of cell types and function as the key Golgi- and plasma membrane-associated SM synthases in human cervical carcinoma HeLa cells, respectively. RNA interference-mediated depletion of either SMS1 or SMS2 caused a substantial decrease in SM production levels, an accumulation of ceramides, and a block in cell growth. Although SMS-depleted cells displayed a reduced SM content, external addition of SM did not restore growth. These results indicate that the biological role of SM synthases goes beyond formation of SM.
AB - Sphingomyelin ( SM) is a vital component of cellular membranes in organisms ranging from mammals to protozoa. Its production involves the transfer of phosphocholine from phosphatidylcholine to ceramide, yielding diacylglycerol in the process. The mammalian genome encodes two known SM synthase ( SMS) isoforms, SMS1 and SMS2. However, the relative contributions of these enzymes to SM production in mammalian cells remained to be established. Here we show that SMS1 and SMS2 are co-expressed in a variety of cell types and function as the key Golgi- and plasma membrane-associated SM synthases in human cervical carcinoma HeLa cells, respectively. RNA interference-mediated depletion of either SMS1 or SMS2 caused a substantial decrease in SM production levels, an accumulation of ceramides, and a block in cell growth. Although SMS-depleted cells displayed a reduced SM content, external addition of SM did not restore growth. These results indicate that the biological role of SM synthases goes beyond formation of SM.
U2 - 10.1074/jbc.M702423200
DO - 10.1074/jbc.M702423200
M3 - Article
SN - 0021-9258
VL - 282
SP - 17537
EP - 17547
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 24
ER -