TY - JOUR
T1 - RIC-8 is required for GPR-1/2-dependent Gα function during asymmetric division of C. elegans embryos
AU - Afshar, Katayoun
AU - Willard, Francis S.
AU - Colombo, Kelly
AU - Johnston, Christopher A.
AU - McCudden, Christopher R.
AU - Siderovski, David P.
AU - Gönczy, Pierre
N1 - Funding Information:
We thank Karine Baumer for technical assistance. We are grateful to Kenneth Miller for his generous gift of RIC-8 antibodies. We thank Michael Glotzer, Michael Koelle, Ron Plasterk, and Viesturs Simanis for reagents as well as Jean-Michel Bellanger, Daniel Constam, and Viesturs Simanis for critical reading of the manuscript. Some strains were obtained from the Caenorhabditis Genetics Center, which is funded by the NIH National Center for Research Resources (NCRR). This work was supported in part by grants from the Swiss National Science Foundation (31-62102.00 and 3100A0-102087 to P.G.) and the U.S. National Institutes of Health (GM62338 and GM065533 to D.P.S.). F.S.W. is an American Heart Association postdoctoral fellow, and C.R.M. is funded by the Natural Sciences and Engineering Research Council of Canada.
PY - 2004/10/15
Y1 - 2004/10/15
N2 - Heterotrimeric G proteins are crucial for asymmetric cell division, but the mechanisms of signal activation remain poorly understood. Here, we establish that the evolutionarily conserved protein RIC-8 is required for proper asymmetric division of one-cell stage C. elegans embryos. Spindle severing experiments demonstrate that RIC-8 is required for generation of substantial pulling forces on astral microtubules. RIC-8 physically interacts with GOA-1 and GPA-16, two Gα subunits that act in a partially redundant manner in one-cell stage embryos. RIC-8 preferentially binds to GDP bound GOA-1 and is a guanine nucleotide exchange factor (GEF) for GOA-1. Our analysis suggests that RIC-8 acts before the GoLoco protein GPR-1/2 in the sequence of events leading to Gα activation. Furthermore, coimmunoprecipitation and in vivo epistasis demonstrate that inactivation of the Gβ subunit GPB-1 alleviates the need for RIC-8 in one-cell stage embryos. Our findings suggest a mechanism in which RIC-8 favors generation of Gα free from Gβγ and enables GPR-1/2 to mediate asymmetric cell division.
AB - Heterotrimeric G proteins are crucial for asymmetric cell division, but the mechanisms of signal activation remain poorly understood. Here, we establish that the evolutionarily conserved protein RIC-8 is required for proper asymmetric division of one-cell stage C. elegans embryos. Spindle severing experiments demonstrate that RIC-8 is required for generation of substantial pulling forces on astral microtubules. RIC-8 physically interacts with GOA-1 and GPA-16, two Gα subunits that act in a partially redundant manner in one-cell stage embryos. RIC-8 preferentially binds to GDP bound GOA-1 and is a guanine nucleotide exchange factor (GEF) for GOA-1. Our analysis suggests that RIC-8 acts before the GoLoco protein GPR-1/2 in the sequence of events leading to Gα activation. Furthermore, coimmunoprecipitation and in vivo epistasis demonstrate that inactivation of the Gβ subunit GPB-1 alleviates the need for RIC-8 in one-cell stage embryos. Our findings suggest a mechanism in which RIC-8 favors generation of Gα free from Gβγ and enables GPR-1/2 to mediate asymmetric cell division.
UR - http://www.scopus.com/inward/record.url?scp=5444260164&partnerID=8YFLogxK
U2 - 10.1016/j.cell.2004.09.026
DO - 10.1016/j.cell.2004.09.026
M3 - Article
C2 - 15479639
AN - SCOPUS:5444260164
VL - 119
SP - 219
EP - 230
JO - Cell
JF - Cell
SN - 0092-8674
IS - 2
ER -