CALHM 1 controls Ca 2 +-dependent MEK / ERK / RSK / MSK signaling in 1 
 neurons 2 
 3

CALHM1 controls Ca2+-dependent MEK/ERK/RSK/MSK signaling in 1
 neurons 2
 3
 Ute Dreses-Werringloer, Valérie Vingtdeux, Haitian Zhao, Pallavi Chandakkar, Peter 4
 Davies, Philippe Marambaud 5
 6
 Litwin-Zucker Research Center for the Study of Alzheimer’s Disease, The Feinstein Institute for 7
 Medical Research, Manhasset, New York, USA. Department of Pathology, Albert Einstein 8
 College of Medicine, Bronx, New York, USA 9
 10
 Correspondence: Philippe Marambaud, Phone: (516) 562-0425, Fax: (516) 562-0401, E-mail: 11
 pmaramba@nshs.edu 12
 13
 Running Title: CALHM1 in neuronal ERK signaling 14
 15
 ABSTRACT: Calcium homeostasis modulator 1 (CALHM1) is a Ca channel controlling 16
 neuronal excitability and potentially involved in the pathogenesis of Alzheimer’s disease (AD). 17
 Although strong evidence indicates that CALHM1 is required for neuronal electrical activity, its 18
 role in intracellular Ca signaling remains unknown. Here, we show that in hippocampal HT-22 19
 cells, CALHM1 expression led to a robust and relatively selective activation of the Ca-sensing 20
 kinases, ERK1/2. CALHM1 also triggered activation of MEK1/2, the upstream ERK1/221
 activating kinases, and of RSK1/2/3 and MSK1, two downstream effectors of ERK1/2 signaling. 22
 CALHM1-mediated activation of ERK1/2 signaling was controlled by the small GTPase Ras. 23
 Pharmacological inhibition of CALHM1 permeability using ruthenium red, Zn, and Gd, or 24
 expression of the CALHM1 N140A and W114A mutants, which are deficient in mediating Ca 25
 influx, prevented the effect of CALHM1 on the MEK/ERK/RSK/MSK signaling cascade, 26
 demonstrating that CALHM1 controlled this pathway via its Ca channel properties. 27
 Importantly, expression of CALHM1 bearing the natural P86L polymorphism, which leads to a 28
 partial loss of CALHM1 function and is associated with an earlier age at onset in AD patients, 29
 showed reduced activation of ERK1/2, RSK1/2/3, and MSK1. In line with these results obtained 30
 in transfected cells, primary cerebral neurons isolated from Calhm1 knockout mice showed 31
 © 2012. Published by The Company of Biologists Ltd.