Antibodies Calmodulin and CaM-kinases

Introduction

Calmodulin acts as an intermediary protein that senses calcium levels and relays signals to various calcium-sensitive enzymes, ion channels and other proteins. This 17 kD protein is composed of two globular domains connected together by a flexible linker. Each end binds to two calcium ions. As it binds calcium, Calmodulin undergoes conformational changes which can increase its affinity for target proteins.

Studies have found that Calmodulin participates in the regulation of several biological processes including energy and biosynthetic metabolism, cell motility, exocytosis, cytoskeletal assembly, and intracellular modulation of both cAMP and calcium concentrations. It acts both directly, through interaction with key target enzymes, and indirectly, via specific kinases. Ca2+/Calmodulin (CaM)-dependent protein kinases (CaMkinases). CaM-kinases constitute a family of structurally related enzymes that include phosphorylase kinase, Myosin light chain kinase, and CaM-kinases I-IV.

There have been identified multiple substrates for CaMK I, including synapsin 1, synapsin 2, CREB, and CFTR, and its activation is dependent upon phosphorylation of Thr177 by CaMKkinase (CaMKK). Studies suggest that CaMK I plays an important role in retinal function and its expression is regulated by light stimulation.

Calcium/Calmodulin-dependent protein kinase 1D-beta isoform is a novel Calmodulin-kinase that exhibits Ca2+/CaM-dependent activity. CaMKK alpha upregulates CaMK ID-beta activity through phosphorylation of its Thr180. CaM-kinase II, one of the best-studied multifunctional enzymes, is found in high concentrations in neuronal synapses, and in some regions of the brain it may constitute up to 2% of the total protein content. Activation of CaM-kinase II has been linked to memory and learning processes in the vertebrate nervous system. In the inactive state there is a strong interaction between the inhibitory and catalytic domains of the enzyme. The binding of Ca2+/CaM allows the catalytic domain to phosphorylate the inhibitory domain. Autophosphorylation of Threonine 286 occurs after Ca2+/Calmodulin activation and can enable CaM-Kinase II to remain active independent of free calcium, thereby prolonging the duration of kinase activity.

CaM-kinase IV (CaMK IV), in a calcium and Calmodulin dependent manner, is implicated in phosphorylating numerous transcription factors including the CCAAT enhancer binding protein (C/EBP), serum response factor (SRF), and cyclic AMP response element binding protein (CBP). The nuclear localization of this protein is consistent with its role in mediating calciumdependent gene expression. CaMK IV is particularly abundant in testis, T-cells, and neurons but is also found in other tissues to varying degrees. In neurons, CaMK IV is thought to play an important role in synaptic plasticity via its gene regulatory effects.

Antibody Panel to Calmodulin and CaM-kinases

Acris Antibodies offers a range of monoclonal and polyclonal antibodies to Calmodulin and Calmodulin-Dependent Protein Kinases (CaMKI, II and IV). The antibodies react in various species and can be used for different applications.

For CaM-Kinase II a panel of phospho-specific antibodies is also available. These antibodies have been raised against two different phosphorylation sites: Thr286 and Thr305.

Fig.1: Staining of Calmodulin in rat brain using antibody SM5111.

Fig.2: Western blot of CaMK I on At20 cell extract using antibody SP5224P.

Fig.3: Western blot of CAMK 1D-beta in human brain cell lysate using antibody SP7340P at 2 µg/ml.

Fig.4: Western blot of CaMK IV in rat brain extract using antibody SP5223P.

Antibody Panel to Calmodulin and CaM-kinases

Calmodulin, CaMK I, CaMK ID-beta, CaMK II antibody.

Literature

Yamanaka A, Hiragami Y, Maeda N, Toku S, Kawahara M, Naito Y, Yamamoto H. Involvement of CaM kinase II in gonadotropin-releasing hormone-induced activation of MAP kinase in cultured hypothalamic neurons. Arch Biochem Biophys. 2007 Oct 15;466(2):234-41.

Kameshita I, Yamada Y, Nishida T, Sugiyama Y, Sueyoshi N, Watanabe A, Asada Y. Involvement of Ca(2+)/calmodulin-dependent protein kinases in mycelial growth of the basidiomycetous mushroom, Coprinus cinereus. Biochim Biophys Acta. 2007 Sep;1770(9):1395-403. Epub 2007 Jun 8

Ishikawa Y, Tokumitsu H, Inuzuka H, Murata-Hori M, Hosoya H, Kobayashi R. Identification and characterization of novel components of a Ca2+/calmodulin-dependent protein kinase cascade in HeLa cells. FEBS Lett. 2003 Aug 28;550(1-3):57-63.

Chin, D. and A.R. Means Mechanisms for regulation of calmodulin kinase IIalpha by Ca2+/calmodulin and autophosphorylation of threonine 286. Biochemistry, 2002, 41(47):14001-14009.

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