The protein with the most predominant Ca2+ binding activity in membrane fractions of the human placenta was purified to electrophoretical homogeneity. This protein was identified as the membrane bound form of calmodulin based on the immunological cross reactivity and a number of biochemical properties. The membrane fraction of the human placenta contained 8.3% of the total cellular calmodulin a...

Calmodulin has been purified from cell bodies of the green alga Chlamydomonas by Ca++-dependent affinity chromatography on fluphenazine-Sepharose 4B. Calmodulin from this primitive organism closely resembles that from bovine brain in a number of properties, including (a) binding to fluphenazine in a Ca++-dependent, reversible manner, (b) functioning as a heat-stable, Ca++-dependent activator of...

Detergent-permeabilized EGFR-T17 fibroblasts, which overexpress the human epidermal growth factor (EGF) receptor, phosphorylate both poly-L-(glutamic acid, tyrosine) and exogenous calmodulin in an EGF-stimulated manner. Phosphorylation of calmodulin requires the presence of cationic polypeptides, such as poly-L-(lysine) or histones, which exert a biphasic effect toward calmodulin phosphorylatio...

Two different calcium-binding proteins, S-100 and calmodulin, have been isolated from bovine brain by calcium-dependent affinity chromatography on calmodulin antagonist coupled to Sepharose. Calmodulin antagonist N-(6-aminohexyl)-5-chloro-l-napthdenesulfonamide (W-7) has been coupled to epoxy-activated Sepharose 6B or cyanogen bromide-acitivated Sepharose 4B. S-100-like protein bound to W-7 cou...

p68 RNA helicase is a prototypical RNA helicase. Here we present evidence to show that, by interacting with Ca-calmodulin, p68 has a role in cancer metastasis and cell migration. A peptide fragment that spans the IQ motif of p68 strongly inhibits cancer metastasis in two different animal models. The peptide interrupts p68 and Ca-calmodulin interaction and inhibits cell migration. Our results de...

The role of spectrin and its association with calmodulin in spreading mouse blastomeres was investigated. Embryonic spectrin binds 125I-calmodulin in a calcium-dependent fashion in the blot overlay technique. Double-labeling experiments show coordinate redistribution of spectrin and calmodulin in blastomeres preparing to undergo active spreading movement. At this stage cortical spectrin stainin...

We used the freshwater protozoan Paramecium tetraurelia to investigate the potential regulation by protein kinase C of calmodulin interactions with binding peptides in intact cells. In these organisms, an action potential results in membrane depolarization and a period of backward swimming; repolarization and a return to forward swimming requires the presence of normal calmodulin. We postulated...

Calmodulin is a soluble, heat-stable protein which has been shown to modulate both membrane-bound and soluble enzymes, but relatively little has been known about the in vivo associations of calmodulin. A 17,000-dalton heat-stable protein was found to move in axonal transport in the guinea pig visual system with the proteins of slow component b (SCb; 2 mm/d) along with actin and the bulk of the ...

Engagement of platelet membrane glycoprotein (GP) Ib-IX-V by von Willebrand factor triggers Ca11-dependent activation of aIIbb3, resulting in (patho)physiological thrombus formation. It is demonstrated here that the cytoplasmic domain of GPIb-IX-V associates with cytosolic calmodulin. First, an anti-GPIba antibody coimmunoprecipitated GPIb-IX and calmodulin from platelet lysates. Following plat...