4M1L

Complex of IQCG and Ca2+-bound CaM

Summary for 4M1L

• Entry DOI: 10.2210/pdb4m1l/pdb
• Related: 4LZX
• Descriptor: Calmodulin, IQ domain-containing protein G, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: calcium signalling, metal binding protein
• Biological source: Homo sapiens (human); More
• Cellular location: Cytoplasm, cytoskeleton, spindle : P62158
• Total number of polymer chains: 2
• Total formula weight: 24807.82

Authors

Liang, W.X.,Chen, L.T.,Chen, Z.,Chen, S.J.,Chen, S. (deposition date: 2013-08-03, release date: 2014-05-07, Last modification date: 2023-11-08)

Primary citation

Chen, L.T.,Liang, W.X.,Chen, S.,Li, R.K.,Tan, J.L.,Xu, P.F.,Luo, L.F.,Wang, L.,Yu, S.H.,Meng, G.,Li, K.K.,Liu, T.X.,Chen, Z.,Chen, S.J.
Functional and molecular features of the calmodulin-interacting protein IQCG required for haematopoiesis in zebrafish
Nat Commun, 5:3811-3811, 2014

PubMed Abstract: We previously reported a fusion protein NUP98-IQCG in an acute leukaemia, which functions as an aberrant regulator of transcriptional expression, yet the structure and function of IQCG have not been characterized. Here we use zebrafish to investigate the role of iqcg in haematopoietic development, and find that the numbers of haematopoietic stem cells and multilineage-differentiated cells are reduced in iqcg-deficient embryos. Mechanistically, IQCG binds to calmodulin (CaM) and acts as a molecule upstream of CaM-dependent kinase IV (CaMKIV). Crystal structures of complexes between CaM and IQ domain of IQCG reveal dual CaM-binding footprints in this motif, and provide a structural basis for a higher CaM-IQCG affinity when deprived of calcium. The results collectively allow us to understand IQCG-mediated calcium signalling in haematopoiesis, and propose a model in which IQCG stores CaM at low cytoplasmic calcium concentrations, and releases CaM to activate CaMKIV when calcium level rises.

PubMed: 24787902
DOI: 10.1038/ncomms4811

Experimental method

X-RAY DIFFRACTION (2.1 Å)