AaCAT1 of the yellow fever mosquito, Aedes aegypti: a novel histidine-specific amino acid transporter from the SLC7 family.
Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to L-histidine at neutral pH (K(0.5)(L-His) = 0.34 ± 0.07 mM, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His(+)-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues.
Department of Biology and Institute of Applied Biosciences, New Mexico State University, Las Cruces, New Mexico 88003-8001, USA. immoh@nmsu.edu
Immo A
IA
Hansen
Dmitri Y
DY
Boudko
Shin-Hong
SH
Shiao
Dmitri A
DA
Voronov
Ella A
EA
Meleshkevitch
Lisa L
LL
Drake
Sarah E
SE
Aguirre
Jeffrey M
JM
Fox
Geoffrey M
GM
Attardo
Alexander S
AS
Raikhel
D000330:Aedes / Q000235:genetics / Q000378:metabolism*; D026905:Amino Acid Transport Systems / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D003001:Cloning, Molecular; D005216:Fat Body / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006639:Histidine / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes; D011679:Pupa / Q000201:enzymology; D014982:Xenopus laevis; D015004:Yellow Fever
D026905:Amino Acid Transport Systems; D019476:Insect Proteins; D006639:Histidine
J Exp Biol. 2006 Aug;209(Pt 16):3183-98
16888066
Pflugers Arch. 2004 Feb;447(5):465-8
14624363
Proc Natl Acad Sci U S A. 2005 Feb 1;102(5):1360-5
15665107
Am J Physiol Renal Physiol. 2002 Jul;283(1):F181-9
12060600
PLoS One. 2010 Mar 01;5(3):e9471
20208991
Pflugers Arch. 2004 Feb;447(5):532-42
14770310
Science. 2009 Aug 21;325(5943):1010-4
19608859
J Biol Chem. 2005 May 27;280(21):20565-72
15788394
Mol Biol Evol. 1987 Jul;4(4):406-25
3447015
Cell. 2003 Sep 19;114(6):739-49
14505573
Development. 2005 May;132(10):2365-75
15843412
Science. 1965 Jan 1;147(3653):68-71
17799782
Annu Rev Entomol. 2010;55:207-25
19725772
Cell Metab. 2007 Oct;6(4):257-66
17908555
Mol Biol Evol. 2007 Aug;24(8):1596-9
17488738
BMC Res Notes. 2010 Oct 04;3:248
20920356
Biochemistry. 2001 Oct 16;40(41):12387-94
11591158
Symp Soc Exp Biol. 1994;48:167-77
7597641
J Exp Biol. 2006 Aug;209(Pt 16):3071-8
16888056
PLoS One. 2010 Dec 29;5(12):e15578
21249121
Physiol Rev. 1998 Apr;78(2):487-545
9562037
Insect Biochem Mol Biol. 2005 Jul;35(7):661-75
15894184
Nature. 2007 Jan 18;445(7125):275-80
17136098
Nature. 1991 Aug 22;352(6337):725-8
1652100
J Membr Biol. 2006;213(2):67-77
17417706
Nucleic Acids Res. 1997 Sep 1;25(17):3389-402
9254694
Proc Natl Acad Sci U S A. 2004 Jul 20;101(29):10626-31
15229322
J Cell Biol. 2006 Jun 19;173(6):963-74
16785324
Mech Dev. 2000 Apr;92(2):155-67
10727855
Evolution. 1985 Jul;39(4):783-791
28561359
Insect Biochem Mol Biol. 2008 Oct;38(10):923-31
18718864
Nucleic Acids Res. 2004 Mar 19;32(5):1792-7
15034147
Comp Biochem Physiol Physiol. 1994 Oct;109(2):361-7
7956120
Anal Biochem. 1987 Apr;162(1):156-9
2440339