RIC8B

RIC8 guanine nucleotide exchange factor B

Ensembl:
ENSG00000111785
UniProt:
Q9NVN3
OMIM:
609147
Synonyms:
HSyn, Synembryn-B, Brain Synembryn, Chaperone Ric-8B, FLJ10620

Cilia effects upon perturbation of RIC8B

Cilia number / % ciliated:
Decreased cilia number
Loss-of-function effect:
Impaired ciliogenesis
Overexpression effect:
Unknown

Phenotypes

Mouse phenotype:
embryonic lethal (RIC-8B knockout)

Subcellular localization

cilia, centrosome, cytosol, plasma membrane, Plasma membrane, Cytosol

Functional category

  • G protein signaling
  • Cilium signaling
  • Ciliary assembly/disassembly
  • Cilia–cytoskeleton/adhesion links

Function

RIC8 paralog of RIC8A. Acts as a guanine nucleotide exchange factor and chaperone for Galpha-s and Galpha-olf subunits. Subcellular localization includes centrosome, cytosol, and plasma membrane (UniProt). C. elegans has a single ric-8 gene whose ortholog functions overlap both mammalian paralogs. Campagna et al. 2026 reported that human RIC8B (alongside RIC8A) is required for ciliogenesis in RPE-1 cells (preprint figures pending direct review). Mouse Ric8b knockout is embryonic lethal.

Model organism evidence

Homo sapiens (RPE-1 cells) (1 reference)

Human RIC8B is required for ciliogenesis in RPE-1 cells alongside RIC8A; depletion of either paralog reduces ciliated cell percentage (Campagna et al. 2026).

PMIDs: 41727026

Mus musculus (0 references)

Ric8b knockout is embryonic lethal in mouse (literature consensus; ciliary phenotype not specifically reported in available papers).

C. elegans (1 reference)

C. elegans has a single ric-8 ortholog whose function spans both mammalian A and B paralogs; localizes to the inversin compartment of channel cilia (Christensen & Nechipurenko 2023).

PMIDs: 37793942