Analysis of the T beta gamma-binding domain of MEKA/phosducin.
MEKA/phosducin, a 33 kDa phosphoprotein in the photoreceptor cell, associates with transducin beta gamma (T beta gamma) with its N-terminal domain (N-terminal 105 amino acids of MEKA), and translocates T beta gamma from the photoreceptor disc membrane to the soluble fraction. The present study further localized the T beta gamma-binding domain to aa 17-105 of MEKA, and showed that the activity of MEKA to translocate T beta gamma depends on the domain. A series of deletion mutant MEKA proteins were prepared to investigate the domain of MEKA which binds to and translocates T beta gamma. Both binding and translocation activities were not impaired by the deletion of the N-terminal 16 amino acids of MEKA, but completely abolished by further deletion to 42Val. Although anti-MEKA serum inhibited the T beta gamma-MEKA association, the antiserum absorbed with a recombinant peptide corresponding to aa 17-105 of MEKA did not, confirming that aa 17-105 of MEKA directly interacts with T beta gamma.
Tanaka
H
H
Department of Pharmacology 1, Osaka University Medical School, Japan.
Iwami
C
C
Kuo
C H
CH
Ding
Y
Y
Do
E
E
Irie
Y
Y
Miki
N
N
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D001692:Biological Transport; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D003600:Cytosol / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism*; D020555:GTP-Binding Protein Regulators; D017353:Gene Deletion; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D010786:Photoreceptor Cells / Q000378:metabolism; D015293:Transducin / Q000378:metabolism*
D005136:Eye Proteins; D020555:GTP-Binding Protein Regulators; D010750:Phosphoproteins; C065631:phosducin; D015293:Transducin