The sea urchin embryo as a model for studying efflux transporters: roles and energy cost.
We describe the use of the sea urchin as a model for studying efflux transporters and estimating energy cost for the cytotoxin protective system provided by these transporters. The unfertilized egg has low transport activity, which increases to a new steady state shortly after fertilization. Activity results from p-glycoprotein (p-gp) and MRP type transporters which protect the embryo from cytotoxic drugs that can disrupt cell division or induce apoptosis. The energy cost is estimated from a novel use of calcein-AM as a substrate; keeping 0.25 microM substrate levels out of the cell utilizes only 0.023% of steady state respiration.
Epel
David
D
Hopkins Marine Station of Stanford University, Pacific Grove, CA 93950, USA. depel@stanford.edu
Cole
Bryan
B
Hamdoun
Amro
A
Thurber
Rebecca Vega
RV
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000502:physiology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D003524:Cyclosporins / Q000494:pharmacology; D003603:Cytotoxins / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005047:Etoposide / Q000633:toxicity; D005452:Fluoresceins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000502:physiology*; D023421:Models, Animal; D011422:Propionates / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D012617:Sea Urchins; D014700:Verapamil / Q000633:toxicity; D014747:Vinblastine / Q000633:toxicity
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D003524:Cyclosporins; D003603:Cytotoxins; D005452:Fluoresceins; D026901:Membrane Transport Proteins; D011422:Propionates; D011804:Quinolines; C085925:calcein AM; C059141:verlukast; D014747:Vinblastine; D005047:Etoposide; D014700:Verapamil; C070272:valspodar