2024-03-29T13:42:24Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/828662020-01-13T12:46:39Zcom_10261_94com_10261_8col_10261_473
Involvement of MRAPs in the function of fish melanocortin receptors (MCRs)
Cerdá-Reverter, José Miguel
Agulleiro Gozalbo, Maria Josep
Cortés, Raúl
Fernández-Durán, Begoña
Sánchez, E.
Guillot, Raúl
Leal, Esther
Ponencia presentada en la 26th Conference of European Comparative Endocrinologists celebrada en Zúrich (Suiza) del 21 al 25 de agosto de 2012
Melanocortin signalling is mediated by binding to a
family of G protein-coupled receptors that
positively couple to adenylyl cyclase. Tetrapod spe
cies have five melanocortin (MC1R-MC5R)
receptors but the number of receptors varies in fis
h. Zebrafish (zf), for example, have six melanocort
in
receptors, with two copies of the melanocortin MC5
receptor, while pufferfish have 4 receptors with
no melanocortin MC3 receptor. MC2R specifically bin
ds ACTH but requires the cooperation of the
melanocortin receptor accessory protein (MRAP) to r
each functional expression. The four other MCRs
distinctively bind MSHs and show low affinity by AC
TH. Two different MRAPs have been
characterized in vertebrates, i.e MRAP1 and MRAP2.
MRAP1 interacts with the MC2R to facilitate
correct folding, subsequent glycosylation and cell
surface expression but it is also essential for ACT
H
binding and ACTH-induced cAMP production. In the ab
sence of MRAP, the MC2R is retained at the
endoplasmic reticulum where it cannot be stimulated
by ACTH. Both MRAP1 and MRAP2 have been
also characterized in fish but, again, the number o
f MRAPs diverges in teleost species. Zebrafish have
three different MRAPs, with two copies of the MRAP2
, i.e MRAP2a and MRAP2b. Similar to
tetrapod, zfMC2R is able to response to ACTH stimul
ation only when coexpressed with MRAP1.
Function of vertebrate MRAP2 is unknown but immunop
recipitation studies demonstrate physical
interaction with MCRs. In mammals, MRAP2 seems to b
e an endogenous inhibitor that competes
with MRAP1 for binding to MC2R anddecrease the pote
ncy of adrenocorticotropic hormone (ACTH).
However, it seems no to be the case in fish. The fu
nction of MRAPs in the fish melanocortin system
will be discussed.
2013-09-26T07:38:47Z
2013-09-26T07:38:47Z
2012
2013-09-26T07:38:47Z
comunicación de congreso
26th Conference of European Comparative Endocrinologists (2012)
http://hdl.handle.net/10261/82866
eng
closedAccess
European Society for Comparative Endocrinology