Functional specialization of calreticulin domains

Nakamura, K.; Zuppini, A.; Arnaudeau, Serge; Lynch, J.; Ahsan, I.; Krause, R.; Papp, S.; De Smedt, H.; Parys, J. B.; Muller-Esterl, W.; Lew, Daniel Pablo; Krause, Karl-Heinz; Demaurex, Nicolas; Opas, M.; Michalak, Marek

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Title		Functional specialization of calreticulin domains
Authors		Nakamura, K. Zuppini, A. Arnaudeau, Serge Lynch, J. Ahsan, I. Krause, R. Papp, S. De Smedt, H. Parys, J. B. Muller-Esterl, W. Lew, Daniel Pablo Krause, Karl-Heinz Demaurex, Nicolas Opas, M. Michalak, Marek show all authors [1 - 15]
Published in		The Journal of Cell Biology. 2001, vol. 154, no. 5, p. 961-972
Abstract		Calreticulin is a Ca2+-binding chaperone in the endoplasmic reticulum (ER), and calreticulin gene knockout is embryonic lethal. Here, we used calreticulin-deficient mouse embryonic fibroblasts to examine the function of calreticulin as a regulator of Ca2+ homeostasis. In cells without calreticulin, the ER has a lower capacity for Ca2+ storage, although the free ER luminal Ca2+ concentration is unchanged. Calreticulin-deficient cells show inhibited Ca2+ release in response to bradykinin, yet they release Ca2+ upon direct activation with the inositol 1,4,5-trisphosphate (InsP3). These cells fail to produce a measurable level of InsP3 upon stimulation with bradykinin, likely because the binding of bradykinin to its cell surface receptor is impaired. Bradykinin binding and bradykinin-induced Ca2+ release are both restored by expression of full-length calreticulin and the N + P domain of the protein. Expression of the P + C domain of calreticulin does not affect bradykinin-induced Ca2+ release but restores the ER Ca2+ storage capacity. Our results indicate that calreticulin may play a role in folding of the bradykinin receptor, which affects its ability to initiate InsP3-dependent Ca2+ release in calreticulin-deficient cells. We concluded that the C domain of calreticulin plays a role in Ca2+ storage and that the N domain may participate in its chaperone functions.
Keywords		Animals — Bradykinin/pharmacology — Calcium/ metabolism — Calcium Channels/genetics/metabolism — Calcium-Binding Proteins/genetics/ metabolism — Calcium-Transporting ATPases/metabolism — Calreticulin — Cell Line — Endoplasmic Reticulum/ metabolism — Enzyme Inhibitors/pharmacology — Fibroblasts/drug effects/physiology — Flow Cytometry — Homeostasis — Immunoblotting — Inositol 1,4,5-Trisphosphate Receptors — Mice — Mice, Knockout — Microscopy, Fluorescence — Molecular Chaperones/genetics/metabolism — Protein Isoforms/genetics/metabolism — Protein Structure, Tertiary — Receptors, Bradykinin/metabolism — Receptors, Cytoplasmic and Nuclear/genetics/metabolism — Ribonucleoproteins/genetics/ metabolism — Sarcoplasmic Reticulum Calcium-Transporting ATPases — Thapsigargin/pharmacology — Transfection
Identifiers		DOI: 10.1083/jcb.200102073 PMID: 11524434
Full text		Article - Limited access to UNIGE Other version: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2196195/pdf/0102073.pdf
Structures		Faculté de médecine / Section de médecine clinique / Département de médecine interne des spécialités
Citation (ISO format)		NAKAMURA, K. et al. Functional specialization of calreticulin domains. In: The Journal of Cell Biology, 2001, vol. 154, n° 5, p. 961-972. https://archive-ouverte.unige.ch/unige:7440