134
Calcium Biochemistry
6.1.1
The Calcium Channel
157
6.1.2
The Ca
2
+
Pump
158
6.1.3
Na
+
/Ca
2
+
Exchanger
161
6.2
Ca
2
+
Transport Systems of the Reticulum
161
6.2.1
The IP
3
Receptor
161
6.2.2
The Ca
2
+
-release Channel
162
6.2.3
The Ca
2
+
Pump
163
6.3
The Mitochondrial Calcium Transporting Systems
165
6.4
Calcium in the Nucleus
165
7
Role of Calcium in Specialized Tissues
166
7.1
Calcium and Fertilization
166
7.2
Calcium in Calcifying Tissues
166
7.3
The Role of Calcium in Plants
167
7.3.1
Touch Genes
167
7.3.2
Calmodulin-like Domain Protein Kinase (CDPK)
167
8
Calcium and Disease
168
9
Conclusions
168
Bibliography
169
Books and Reviews
169
Primary Literature
169
Keywords
Calcium
The ±fth most abundant element of the human body; it has a stabilizing function in
shells, bones, and teeth (bound as hydroxyapatite), and in proteins in the extracellular
fluid. Inside cells, calcium functions as a second messenger by interacting with speci±c
Ca
2
+
binding proteins (e.g. calmodulin).
Calmodulin
A highly conserved, intracellular Ca
2
+
binding sensor protein involved in triggering
Ca
2
+
signals. It contains four helix-loop-helix or EF-hand Ca
2
+
binding domains.
Channel
Integral membrane proteins responsible for transport across membranes; opening and
closing (i.e. gating) can be voltage-, ligand-, or store-operated.
EF-hand Proteins
The term coined by R.H. Kretsinger to describe the helix-loop-helix calcium binding
domains of speci±c proteins. The highly conserved motif (±rst described on the basis of
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