REGULAR ARTICLES
Cell Research (1998)8:303-310
© 1998 SIBS, CAS All rights reserved 1001-0602/98
Carboxyl terminal of rhodopsin kinase is required for the phosphorylation
of photo-activated rhodopsin.
Yu QM, Cheng ZJ, Zhao J, Zhou TH, Wu YL, MA L, Pei G.
Shanghai Institute of Cell Biology, Chinese Academy of Science, China.
Human rhodopsin kinase (RK) and a carboxyl terminus-truncated mutant RK
lacking the last 59 amino acids (RKC) were expressed in human embryonic
kidney 293 cells to investigate the role of the carboxyl terminus of RK
in recognition and phosphorylation of rhodopsin. RKC, like the wild-type
RK, was detected in both plasma membranes and cytosolic fractions. The C-terminal
truncated rhodopsin kinase was unable to phosphorylate photo-activated rhodopsin,
but possesses kinase activity similar to the wild-type RK in phosphorylation
of small peptide substrate. It suggests that the truncation did not disturb
the gross structures of RK catalytic domain. Our results also show that
RKC failed to translocate to photo-activated rod out segments. Taken together,
our study demonstrate the carboxyl terminus of RK is required for phosphorylation
of photo-activated rhodopsin and strongly indicate that carboxyl-terminus
of RK may be involved in interaction with photo-activated rhodopsin.
Keywords : Rhodopsin
kinase, phosphorylation, fruncation. |
