KBTBD7 (13q14.11) , Transkriptioktivaattori . Tekee adaptorina trimeerin KTBTD6 ja CUL3 kanssa .

https://www.ncbi.nlm.nih.gov/gene/84078

Summary

The protein encoded by this gene is a transcriptional activator, having been shown to increase the transcription of activator protein-1 and serum response element. The encoded protein can also form a complex with KBTBD6 and CUL3, which regulates the ubiquitylation and degradation of TIAM1, which is a regulator of RAC1. [provided by RefSeq, Jul 2016]

https://www.ncbi.nlm.nih.gov/protein/NP_115514.2
https://www.sciencedirect.com/science/article/pii/S1097276514010181

 https://marlin-prod.literatumonline.com/cms/attachment/6450de6a-5936-4482-baf6-024a218a8e3e/fx1.jpg

Summary

The small Rho GTPase RAC1 is an essential regulator of cellular signaling that controls actin rearrangements and cell motility. Here, we identify a novel CUL3 RING ubiquitin ligase complex, containing the substrate adaptors KBTBD6 and KBTBD7, that mediates ubiquitylation and proteasomal degradation of TIAM1, a RAC1-specific GEF. 

Increasing the abundance of TIAM1 by depletion of KBTBD6 and/or KBTBD7 leads to elevated RAC1 activity, changes in actin morphology, loss of focal adhesions, reduced proliferation, and enhanced invasion. 

 KBTBD6 and KBTBD7 employ ATG8 family-interacting motifs to bind preferentially to GABARAP proteins.

 Surprisingly, ubiquitylation and degradation of TIAM1 by CUL3^{KBTBD6/KBTBD7} depends on its binding to GABARAP proteins.

 Our study reveals that recruitment of CUL3^{KBTBD6/KBTBD7} to GABARAP-containing vesicles regulates the abundance of membrane-associated TIAM1 and subsequently spatially restricted RAC1 signaling. Besides their role in autophagy and trafficking, we uncovered a previously unknown function of GABARAP proteins as membrane-localized signaling scaffolds.