By binding to their cognate GPCRs, many potent
mitogens such as neuropeptides, angiotensin II or
lysophosphatidic acid stimulate cell proliferation via engaging
the ERK/MAPK cascade. As mentioned before, agonists stimulating
Gq/11-coupled receptors activate PLCb isoforms thereby
activating PKCs and elevating [Ca2+]i. These two second
messengers represent key molecules for coupling Gq/11 proteins
to the ERK/MAPK cascade. In this work, by means of GnRH in
gonadotropic aT3-1 cells and galanin or bradykinin in SCLC
cells, different aspects of Gq/11-dependent mitogenic signaling
pathways were revealed. Our findings together with previous
reports underline the notion that signaling pathways emanating
from Gq/11-coupled receptors are tightly regulated in a cell-
and receptor-specific manner.
