Annexins sense changes in intracellular pH during hypoxia

Monastyrskaya, Katia; Tschumi, Fabian; Babiychuk, Eduard B; Stroka, Deborah; Draeger, Annette (2008). Annexins sense changes in intracellular pH during hypoxia. Biochemical journal, 409(1), pp. 65-75. London: Portland Press 10.1042/BJ20071116

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The pH(i) (intracellular pH) is an important physiological parameter which is altered during hypoxia and ischaemia, pathological conditions accompanied by a dramatic decrease in pH(i). Sensors of pH(i) include ion transport systems which control intracellular Ca2+ gradients and link changes in pH(i) to functions as diverse as proliferation and apoptosis. The annexins are a protein family characterized by Ca2+-dependent interactions with cellular membranes. Additionally, in vitro evidence points to the existence of pH-dependent, Ca(2+)-independent membrane association of several annexins. We show that hypoxia promotes the interaction of the recombinant annexin A2-S100A10 (p11) and annexin A6 with the plasma membrane. We have investigated in vivo the influence of the pH(i) on the membrane association of human annexins A1, A2, A4, A5 and A6 tagged with fluorescent proteins, and characterized this interaction for endogenous annexins present in smooth muscle and HEK (human embryonic kidney)-293 cells biochemically and by immunofluorescence microscopy. Our results show that annexin A6 and the heterotetramer A2-S100A10 (but not annexins A1, A4 and A5) interact independently of Ca2+ with the plasma membrane at pH 6.2 and 6.6. The dimerization of annexin A2 within the annexin A2-S100A10 complex is essential for the pH-dependent membrane interaction at this pH range. The pH-induced membrane binding of annexins A6 and A2-S100A10 might have consequences for their functions as membrane organizers and channel modulators.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Cell Biology 04 Faculty of Medicine > Department of Gastro-intestinal, Liver and Lung Disorders (DMLL) > Clinic of Visceral Surgery and Medicine > Visceral Surgery 04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy
UniBE Contributor:	Babiichuk, Eduard, Stroka, Deborah, Draeger, Annette
ISSN:	0264-6021
ISBN:	17824845
Publisher:	Portland Press
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:55
Last Modified:	02 Mar 2023 23:22
Publisher DOI:	10.1042/BJ20071116
PubMed ID:	17824845
Web of Science ID:	000252414300006
URI:	https://boris.unibe.ch/id/eprint/23522 (FactScience: 42196)