Table 2.

List of biological functions of Bardet-Biedl syndrome proteins

Biological functions of BBS proteins	Description	Reference(s)
Ciliary trafficking	BBS1, BBS4, BBS5, and BBS7 mediate the trafficking of several GPCRs, including Smo and GPR161, to the PC; BBS1 and BBS3 target polycystin 1 and 2 to the PC	Zhang et al.,30 Berbari et al.,62 and Su et al.69
Endosomal trafficking	BBS1 and BBS4 are required for delivering Notch receptor to the plasma membrane via endosomal trafficking	Leitch et al.71
Cytoskeleton organization	BBS4, BBS6 and BBS8 regulate actin polymerization by modulation of RhoA activity; BBIP10/ BBS18 is required for cytoplasmic MT polymerization and acetylation	Hernandez-Hernandez et al.45 and Loktev et al.72
Cell division	BBS4 and BBS6 depletion cause cytokinesis defects and produce multinucleate/multicentrosomal cells	Kim et al.36,37
Regulation of proteasomal activity	BBS4 interacts with the proteosomal subunit RPN10BBS11/TRIM32, an E3 ubiquitin ligase promoting several target degradation	Zhang et al.30 and Gerdes et al.73
ER stress response	BBS4 is localized to the ER and participates in UPR activation through regulation of ATF6α and IRE1α	Anosov and Birk48
Regulation of gene expression	BBS7 enters the nucleus and interacts with the chromatin remodeler RNF2, regulating the transcription of its target genes; BBS1–6 and BBS9–11 possess NESs, suggesting a possible nuclear localization in mammalian cells	Gascue et al.47

ER, endoplasmic reticulum; GPCR, G protein–coupled receptor; MT, microtubule; NES, nuclear export signal; UPR, unfolding protein response.