Quantitative analysis of self-association and mobility of Annexin A4 at the plasma membrane

Kevin C. Crosby, Marten Postma, Mark A. Hink, Christiaan H.C. Zeelenberg, Merel J.W. Adjobo-Hermans, Theodorus W.J. Gadella*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

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 Ca2+ 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 Ca2+ 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.

Original languageEnglish
Pages (from-to)1875-1885
Number of pages11
JournalBiophysical Journal
Volume104
Issue number9
DOIs
Publication statusPublished - 7 May 2013
Externally publishedYes

Fingerprint

Dive into the research topics of 'Quantitative analysis of self-association and mobility of Annexin A4 at the plasma membrane'. Together they form a unique fingerprint.

Cite this