BBSome

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BBSome is a protein complex that supplies the cilia with new proteins and plays an important role in intraflagellar transport . The complex was discovered in 2007.

construction

The BBSome protein complex is made up of the proteins BBS1, 2, 4, 5, 7, 8 and 9. Each of them has its own function outside of the BBSome, for example BBS5 prevents ciliogenesis by binding to phosphoinositides . As a complex, BBSome continues to stabilize the IFT-A and IFT-B sub-complexes in the basal body and ciliate tip. BBSome has to be completely present for this, for example the loss of the proteins BBS7 and BBS8 leads to the decay of IFT-A and IFT-B.

function

Mainly, the BBSome complex supplies the cilia with new protein building blocks. It assembles IFT complexes in the basal body of the primary cilia and helps with their anterograde transport into the tip of the cilia. To do this, a pilot, the ARL6 protein , binds to BBS1 and guides the protein complex and its cargo to the cell surface. Once there, BBSome also helps to recycle the cargo and change direction to the base, making it an indispensable part of the transportation system. The interaction of IFT-A complexes with BBS1 has also been demonstrated in mice, while experiments with yeast have shown that IFT-B complexes bind to BBS7.

Ciliopathies

A point mutation in one of the genes coding for the individual components is usually considered to be the main cause of many ciliopathies . A mutation in the gene coding for BBS1 is also the cause in 30% of all cases for Laurence-Moon-Bardet-Biedl syndrome (LMBBS) .

Individual evidence

  1. ↑ a b c d e ciliajournal.com: Intraflagellar transport complex structure and cargo interactions
  2. ↑ a b ubm.opus.hbz-nrw.de: Intraflagellar transport in the developing and mature vertebrate retina ( Memento of the original from January 14, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / ubm.opus.hbz-nrw.de
  3. ↑ nature.com: The BBSome controls IFT assembly and turnaround in cilia
  4. ↑ a b c jsc.biologists.org: Intraflagellar transport at a glance
  5. ↑ cell.com: A Core Complex of BBS protein Cooperates with the GTPase Rab8 to Promote ciliary membrane Biogenesis
  6. ↑ nature.com: Structural basis for membrane targeting of the BBSome by? ARL6