A mutation in Sec15l1 causes anemia in hemoglobin deficit (hbd) mice.
Hemoglobin deficit (hbd) mice carry a spontaneous mutation that impairs erythroid iron assimilation but does not cause other defects. Normal delivery of iron to developing erythroid precursors is highly dependent on the transferrin cycle. Through genetic mapping and complementation experiments, we show that the hbd mutation is an in-frame deletion of a conserved exon of the mouse gene Sec15l1, encoding one of two Sec15 proteins implicated in the mammalian exocyst complex. Sec15l1 is linked to the transferrin cycle through its interaction with Rab11, a GTPase involved in vesicular trafficking. We propose that inactivation of Sec15l1 alters recycling of transferrin cycle endosomes and increases the release of transferrin receptor exocytic vesicles. This in turn decreases erythroid iron uptake. Determining the molecular basis of the hbd phenotype provides new insight into the intricate mechanisms necessary for normal erythroid iron uptake and the function of a mammalian exocyst protein.
Lim
Jackie E
JE
Division of Hematology/Oncology, Children's Hospital Boston, Karp Family Research Laboratories RM 8-125, Boston, Massachusetts 02115-5737, USA.
Jin
Ou
O
Bennett
Carolyn
C
Morgan
Kelly
K
Wang
Fudi
F
Trenor
Cameron C
CC
Fleming
Mark D
MD
Andrews
Nancy C
NC
D000740:Anemia / Q000235:genetics*; D000818:Animals; D016026:Bone Marrow Transplantation; D011992:Endosomes / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005816:Genetic Complementation Test; D006454:Hemoglobins / Q000172:deficiency* / Q000235:genetics; D007501:Iron / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000235:genetics*; D011990:Receptors, Transferrin / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics; D017384:Sequence Deletion; D014168:Transferrin / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
D019204:GTP-Binding Proteins; D006454:Hemoglobins; D007501:Iron; D008565:Membrane Proteins; D011990:Receptors, Transferrin; D014168:Transferrin; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C489222:EXOC6B protein, human; C506790:Sec15 protein, mouse