2BE6

2.0 A crystal structure of the CaV1.2 IQ domain-Ca/CaM complex

Summary for 2BE6

• Entry DOI: 10.2210/pdb2be6/pdb
• Descriptor: Calmodulin 2, Voltage-dependent L-type calcium channel alpha-1C subunit, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: calmodulin, calcium channel, iq domain, inactivation, facilitation, calcium-dependent, gating, voltage-gated, membrane protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 6
• Total formula weight: 64673.44

Authors

Van Petegem, F.,Chatelain, F.C.,Minor Jr., D.L. (deposition date: 2005-10-23, release date: 2005-11-15, Last modification date: 2024-05-22)

Primary citation

van Petegem, F.,Chatelain, F.C.,Minor Jr., D.L.
Insights into voltage-gated calcium channel regulation from the structure of the Ca(V)1.2 IQ domain-Ca(2+)/calmodulin complex
Nat.Struct.Mol.Biol., 12:1108-1115, 2005

PubMed Abstract: Changes in activity-dependent calcium flux through voltage-gated calcium channels (Ca(V)s) drive two self-regulatory calcium-dependent feedback processes that require interaction between Ca(2+)/calmodulin (Ca(2+)/CaM) and a Ca(V) channel consensus isoleucine-glutamine (IQ) motif: calcium-dependent inactivation (CDI) and calcium-dependent facilitation (CDF). Here, we report the high-resolution structure of the Ca(2+)/CaM-Ca(V)1.2 IQ domain complex. The IQ domain engages hydrophobic pockets in the N-terminal and C-terminal Ca(2+)/CaM lobes through sets of conserved 'aromatic anchors.' Ca(2+)/N lobe adopts two conformations that suggest inherent conformational plasticity at the Ca(2+)/N lobe-IQ domain interface. Titration calorimetry experiments reveal competition between the lobes for IQ domain sites. Electrophysiological examination of Ca(2+)/N lobe aromatic anchors uncovers their role in Ca(V)1.2 CDF. Together, our data suggest that Ca(V) subtype differences in CDI and CDF are tuned by changes in IQ domain anchoring positions and establish a framework for understanding CaM lobe-specific regulation of Ca(V)s.

PubMed: 16299511
DOI: 10.1038/nsmb1027

Experimental method

X-RAY DIFFRACTION (2 Å)