Effects of Metal-Binding Loop Mutations on Ligand Binding to Calcium- and Integrin-Binding Protein 1. Evolution of the EF-Hand?†

Biochemistry ◽  
2008 ◽  
Vol 47 (6) ◽  
pp. 1696-1707 ◽  
Author(s):  
Aaron P. Yamniuk ◽  
Jessica L. Gifford ◽  
Sara Linse ◽  
Hans J. Vogel
Keyword(s):  
Ligand Binding ◽  
Metal Binding ◽  
Binding Protein ◽  
Ef Hand ◽  
Binding Loop

scholarly journals Odorant-binding protein. Characterization of ligand binding.

1990 ◽  
Vol 265 (11) ◽  
pp. 6118-6125
Author(s):  
J Pevsner ◽  
V Hou ◽  
A M Snowman ◽  
S H Snyder
Keyword(s):  
Ligand Binding ◽  
Binding Protein ◽  
Protein Characterization ◽  
Odorant Binding Protein ◽  
Odorant Binding

scholarly journals The EF-Hand Ca2+-binding Protein p22 Plays a Role in Microtubule and Endoplasmic Reticulum Organization and Dynamics with Distinct Ca2+-binding Requirements

2004 ◽  
Vol 15 (2) ◽  
pp. 481-496 ◽  
Author(s):  
Josefa Andrade ◽  
Hu Zhao ◽  
Brian Titus ◽  
Sandra Timm Pearce ◽  
Margarida Barroso
Keyword(s):  
Endoplasmic Reticulum ◽  
Conformational Changes ◽  
Membrane Trafficking ◽  
Secretory Pathway ◽  
Network Formation ◽  
Binding Protein ◽  
Dependent Manner ◽  
Microtubule Depolymerization ◽  
Independent Manner ◽  
Ef Hand

We have reported that p22, an N-myristoylated EF-hand Ca2+-binding protein, associates with microtubules and plays a role in membrane trafficking. Here, we show that p22 also associates with membranes of the early secretory pathway membranes, in particular endoplasmic reticulum (ER). On binding of Ca2+, p22's ability to associate with membranes increases in an N-myristoylation-dependent manner, which is suggestive of a nonclassical Ca2+-myristoyl switch mechanism. To address the intracellular functions of p22, a digitonin-based “bulk microinjection” assay was developed to load cells with anti-p22, wild-type, or mutant p22 proteins. Antibodies against a p22 peptide induce microtubule depolymerization and ER fragmentation; this antibody-mediated effect is overcome by preincubation with the respective p22 peptide. In contrast, N-myristoylated p22 induces the formation of microtubule bundles, the accumulation of ER structures along the bundles as well as an increase in ER network formation. An N-myristoylated Ca2+-binding p22 mutant, which is unable to undergo Ca2+-mediated conformational changes, induces microtubule bundling and accumulation of ER structures along the bundles but does not increase ER network formation. Together, these data strongly suggest that p22 modulates the organization and dynamics of microtubule cytoskeleton in a Ca2+-independent manner and affects ER network assembly in a Ca2+-dependent manner.

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