Quantitative analysis of self-association and mobility of annexin A4 at the plasma membrane.
Biophys J
; 104(9): 1875-85, 2013 May 07.
Article
em En
| MEDLINE
| ID: mdl-23663830
ABSTRACT
Annexins, found in most eukaryotic species, are cytosolic proteins that are able to bind negatively-charged phospholipids in a calcium-dependent manner. Annexin A4 (AnxA4) has been implicated in diverse cellular processes, including the regulation of exocytosis and ion-transport; however, its precise mechanistic role is not fully understood. AnxA4 has been shown to aggregate on lipid layers upon Ca(2+) binding in vitro, a characteristic that may be critical for its function. We have utilized advanced fluorescence microscopy to discern details on the mobility and self-assembly of AnxA4 after Ca(2+) influx at the plasma membrane in living cells. Total internal reflection microscopy in combination with Förster resonance energy transfer reveals that there is a delay between initial plasma membrane binding and the beginning of self-assembly and this process continues after the cytoplasmic pool has completely relocated. Number-and-brightness analysis suggests that the predominant membrane bound mobile form of the protein is trimeric. There also exists a pool of AnxA4 that forms highly immobile aggregates at the membrane. Fluorescence recovery after photobleaching suggests that the relative proportion of these two forms varies and is correlated with membrane morphology.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Membrana Celular
/
Anexina A4
/
Multimerização Proteica
Tipo de estudo:
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
Biophys J
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Holanda