ESCRT kompleksissa fosfoinositidit tärkeitä

• https://www.ncbi.nlm.nih.gov/pubmed/26929449

J Cell Biol. 2016 Feb 29;212(5):499-513. doi: 10.1083/jcb.201507009.

ALIX and ESCRT-I/II function as parallel ESCRT-III recruiters in cytokinetic abscission.

Christ L¹, Wenzel EM¹, Liestøl K², Raiborg C¹, Campsteijn C³, Stenmark H³.

Abstract

Cytokinetic abscission, the final stage of cell division where the two daughter cells are separated, is mediated by the endosomal sorting complex required for transport (ESCRT) machinery. The ESCRT-III subunit CHMP4B is a key effector in abscission, whereas its paralogue, CHMP4C, is a component in the abscission checkpoint that delays abscission until chromatin is cleared from the intercellular bridge. How recruitment of these components is mediated during cytokinesis remains poorly understood, although the ESCRT-binding protein ALIX has been implicated. Here, we show that ESCRT-II and the ESCRT-II-binding ESCRT-III subunit CHMP6 cooperate with ESCRT-I to recruit CHMP4B, with ALIX providing a parallel recruitment arm. In contrast to CHMP4B, we find that recruitment of CHMP4C relies predominantly on ALIX. Accordingly, ALIX depletion leads to furrow regression in cells with chromosome bridges, a phenotype associated with abscission checkpoint signaling failure. Collectively, our work reveals a two-pronged recruitment of ESCRT-III to the cytokinetic bridge and implicates ALIX in abscission checkpoint signaling.

Comment in

• Burning cellular bridges: Two pathways to the big breakup. [J Cell Biol. 2016]

 Huom. Geeni ALIX on muilta nimiltä
 DRIP4, Dopamine Receptor Interacting Protein 4;
PDCD6IP , Programmed Cell death 6 Interacting protein
AIP1 ,
ALG-2 interacting protein 1  (or X)
Apoptosis Linked Gene 2 interacting protein X
HP95,
(Hiiren vastaava geeni on Bro1)

https://www.nature.com/articles/s41598-017-09467-9

• https://www.ncbi.nlm.nih.gov/pubmed/28419521

J Cell Biochem. 2017 Nov;118(11):3561-3568. doi: 10.1002/jcb.26066. Epub 2017 May 30.

Cytokinetic Abscission: Phosphoinositides and ESCRTs Direct the Final Cut.

Gulluni F¹, Martini M¹, Hirsch E¹.

Abstract

Cytokinetic abscission involves the fine and regulated recruitment of membrane remodeling proteins that participate in the abscission of the intracellular bridge that connects the two dividing cells. This essential process is mediated by the concomitant activity of the endosomal sorting complex required for transport (ESCRT) and the vesicular trafficking directed to the midbody. Phosphoinositides (PtdIns), produced at plasma membrane, and endosomes, act as molecular intermediates by recruiting effector proteins involved in multiple cellular processes, such as intracellular signaling, endo- and exo-cytosis, and membrane remodeling events. Emerging evidences suggest that PtdIns have an active role in recruiting key elements that control the stability and the remodeling of the cytoskeleton from the furrow ingression to the abscission, at the end of cytokinesis. Accordingly, a possible concomitant and coordinated activity between PtdIns production and ESCRT machinery assembly could also exist and recent findings are pointing the attention on poorly understood ESCRT subunits potentially able to associate with PtdIns rich membranes. Although further studies are required to link PtdIns to ESCRT machinery during abscission, this might represent a promising field of study. J. Cell. Biochem. 118: 3561-3568, 2017.

© 2017 Wiley Periodicals, Inc.

KEYWORDS:

CYTOKINESIS; ESCRT; PHOSPHOINOSITIDES