Expression of GM-CSF receptors in male germ cells and their role in signaling for increased glucose and vitamin C transport.
We studied the expression and function of the granulocyte-macrophage colony stimulating factor (GM-CSF) receptor in male germ cells. RT-PCR showed expression of mRNAs encoding the alpha- and beta-subunits of the GM-CSF receptor in human testis, and the presence of the alpha- and beta-proteins was confirmed by immunoblotting with anti-alpha and anti-beta-antibodies. Immunolocalization studies showed the level of expression of GM-CSF alpha- and beta-subunits in the germ line in the testis and in ejaculated spermatozoa. Receptor binding studies using radiolabeled GM-CSF revealed that bull spermatozoa have about 105 high-affinity sites with a K(d) of 222 pM and approximately 1100 low-affinity sites with a K(d) of 10 nM. GM-CSF signaled, in a time- and dose-dependent manner, for an increased uptake of glucose and vitamin C.
Zambrano
A
A
Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
Noli
C
C
Rauch
M C
MC
Werner
E
E
Brito
M
M
Amthauer
R
R
Slebe
J C
JC
Vera
J C
JC
Concha
I I
II
D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D004587:Electrophoresis, Agar Gel; D005947:Glucose / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007700:Kinetics; D008297:Male; D011485:Protein Binding; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012661:Semen / Q000378:metabolism; D015398:Signal Transduction; D013094:Spermatozoa / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D013997:Time Factors
D012333:RNA, Messenger; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D005947:Glucose; D001205:Ascorbic Acid