Microtubule assembly by the Apc protein is regulated by importin-beta--RanGTP.

J Cell Sci

Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.

Published: March 2010

Mutations in the tumour suppressor Adenomatous polyposis coli (Apc) initiate most sporadic colorectal cancers. Apc is implicated in regulating microtubule (MT) dynamics in interphase and mitosis. However, little is known about the underlying mechanism or regulation of this Apc function. We identified importin-beta as a binding partner of Apc that regulates its effect on MTs. Apc binds importin-beta in vitro and in Xenopus egg extracts, and RanGTP inhibits this interaction. The armadillo-like repeat domain of importin-beta binds to the middle of Apc, where it can compete with beta-catenin. In addition, two independent sites in the C terminus of Apc bind the N-terminal region of importin-beta. Binding to importin-beta reduces the ability of Apc to assemble and bundle MTs in vitro and to promote assembly of microtubule asters in Xenopus egg extracts, but does not affect the binding of Apc to MTs or to EB1. Depletion of Apc decreases the formation of cold-stable spindles in Xenopus egg extracts. Importantly, the ability of purified Apc to rescue this phenotype was reduced when it was constitutively bound to importin-beta. Thus, importin-beta binds to Apc and negatively regulates the MT-assembly and spindle-promoting activity of Apc in a Ran-regulatable manner.

Download full-text PDF

Source
http://dx.doi.org/10.1242/jcs.060806DOI Listing

Publication Analysis

Top Keywords

apc
14
xenopus egg
12
egg extracts
12
importin-beta binding
8
importin-beta binds
8
importin-beta
7
microtubule assembly
4
assembly apc
4
apc protein
4
protein regulated
4

Similar Publications

Importance: The 2009 US Preventive Services Task Force breast cancer screening guideline changes led to decreases in screening mammography, raising concern about potential increases in late-stage disease and more invasive surgical treatments.

Objective: To investigate the incidence of breast cancer by stage at diagnosis and surgical treatment before and after the 2009 guideline changes.

Design, Setting, And Participants: This population-based, epidemiologic cohort study of women aged 40 years or older used 2004 to 2019 data from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program.

View Article and Find Full Text PDF

is a globally distributed human fungal pathogen that can cause cryptococcal meningitis with high morbidity and mortality. In this study, we identified an anaphase-promoting complex (APC) activator, Cdh1, and examined its impact on the virulence of . Our subcellular localization analysis revealed that Cdh1 is situated in the nucleus of .

View Article and Find Full Text PDF

Background: Leprosy control remains challenging in Brazil and has been aggravated by the COVID-19 pandemic.

Objective: To analyze the impact of the COVID-19 pandemic on the epidemiological scenario of leprosy through the detection rate of new cases, the risk of illness, and the hidden prevalence of leprosy according to high-risk micro-region in Minas Gerais, Brazil.

Methods: An ecological study conducted in the health micro-regions of Minas Gerais, using data on new leprosy cases diagnosed between 2015 and 2023.

View Article and Find Full Text PDF

Epidermal growth factor receptor (EGFR) inhibition is crucial in treating RAS wild-type metastatic colorectal cancer, yet current testing methods may miss rare RAS variants affecting treatment efficacy. We analyzed 4122 colorectal cancer patients receiving anti-EGFR antibodies from the Center for Cancer Genomics and Advanced Therapeutics database, identifying 54 patients (1.3%) with rare RAS variants undetectable by standard testing.

View Article and Find Full Text PDF

Background: Colorectal cancer is the third most common malignancy globally. Early-onset colorectal cancer (EOCRC) is becoming a growing healthcare focus globally, particularly in North America. We estimated trends in incidence, mortality, and disability-adjusted life years (DALYs) for EOCRC in Canada between 1990 and 2019.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!