3wut
From Proteopedia
Structure basis of inactivating cell abscission
Structural highlights
Function[CEP55_HUMAN] Plays a role in mitotic exit and cytokinesis. Not required for microtubule nucleation. Recruits PDCD6IP and TSG101 to midbody during cytokinesis.[1] [2] [TEX14_HUMAN] Required both for the formation of intercellular bridges during meiosis and for kinetochore-microtubule attachment during mitosis. Intercellular bridges are evolutionarily conserved structures that connect differentiating germ cells and are required for spermatogenesis and male fertility. Acts by promoting the conversion of midbodies into intercellular bridges via its interaction with CEP55: interaction with CEP55 inhibits the interaction between CEP55 and PDCD6IP/ALIX and TSG101, blocking cell abscission and leading to transform midbodies into intercellular bridges. Also plays a role during mitosis: recruited to kinetochores by PLK1 during early mitosis and regulates the maturation of the outer kinetochores and microtubule attachment. Has no protein kinase activity in vitro (By similarity). Publication Abstract from PubMedIntercellular bridges are a conserved feature of spermatogenesis in mammalian germ cells and derive from arresting cell abscission at the final stage of cytokinesis. However, it remains to be fully understood how germ cell abscission is arrested in the presence of general cytokinesis components. The TEX14 (testis-expressed gene 14) protein is recruited to the midbody and plays a key role in the inactivation of germ cell abscission. To gain insights into the structural organization of TEX14 at the midbody, we have determined the crystal structures of the EABR [endosomal sorting complex required for transport (ESCRT) and ALIX-binding region] of CEP55 bound to the TEX14 peptide (or its chimeric peptides) and performed functional characterization of the CEP55-TEX14 interaction by multiexperiment analyses. We show that TEX14 interacts with CEP55-EABR via its AxGPPx3Y (Ala793, Gly795, Pro796, Pro797, and Tyr801) and PP (Pro803 and Pro804) sequences, which together form the AxGPPx3YxPP motif. TEX14 competitively binds to CEP55-EABR to prevent the recruitment of ALIX, which is a component of the ESCRT machinery with the AxGPPx3Y motif. We also demonstrate that a high affinity and a low dissociation rate of TEX14 to CEP55, and an increase in the local concentration of TEX14, cooperatively prevent ALIX from recruiting ESCRT complexes to the midbody. The action mechanism of TEX14 suggests a scheme of how to inactivate the abscission of abnormal cells, including cancer cells. Structural and biochemical insights into the role of testis-expressed gene 14 (TEX14) in forming the stable intercellular bridges of germ cells.,Kim HJ, Yoon J, Matsuura A, Na JH, Lee WK, Kim H, Choi JW, Park JE, Park SJ, Kim KT, Chang R, Lee BI, Yu YG, Shin YK, Jeong C, Rhee K, Lee HH Proc Natl Acad Sci U S A. 2015 Sep 21. pii: 201418606. PMID:26392564[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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