Probing the in vivo function of Mad1:C-Mad2 in the spindle assembly checkpoint.
EMBO J
; 30(16): 3322-36, 2011 Jul 19.
Article
in En
| MEDLINE
| ID: mdl-21772247
ABSTRACT
The spindle assembly checkpoint (SAC) restrains anaphase until all chromosomes become bi-oriented on the mitotic spindle. The SAC protein Mad2 can fold into two distinct conformers, open (O) and closed (C), and can asymmetrically dimerize. Here, we describe a monoclonal antibody that specifically recognizes the dimerization interface of C-Mad2. This antibody revealed several conformation-specific features of Mad2 in human cells. Notably, we show that Mad2 requires association with Mad1 to adopt the closed conformation and that the activity of the Mad1C-Mad2 complex undergoes regulation by p31comet-dependent 'capping'. Furthermore, C-Mad2 antibody microinjection caused an abrupt termination of the SAC and accelerated mitotic progression. Remarkably, microinjection of a Mad1-neutralizing antibody triggered a comparable mitotic acceleration. Our study provides direct in vivo evidence for the model that a kinetochore complex of Mad1C-Mad2 acts as a template to sustain the SAC and it challenges the distinction between SAC and mitotic timer.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Repressor Proteins
/
Calcium-Binding Proteins
/
Nuclear Proteins
/
Cell Cycle Proteins
/
Adaptor Proteins, Signal Transducing
/
Anaphase
/
Spindle Apparatus
Type of study:
Prognostic_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
EMBO J
Year:
2011
Type:
Article
Affiliation country:
Switzerland