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GTP gamma S-induced solubilization of actin and myosin from rabbit peritoneal neutrophil membrane
Abstract:
Addition of guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) to the membrane fraction isolated from rabbit peritoneal neutrophils results in the solubilization of several proteins from the membrane. The major proteins are of 180 kDa (myosin) and 43 kDa (actin). The effect is observed with a half-maximum GTP gamma S concentration of 70 microM. The potencies of various nucleotides are compared: GTP gamma S greater than GTP greater than ATP greater than GDP, GMP, cGMP, cAMP. The effect does not require calcium and is not inhibited by using membranes prepared from cells that have been pretreated with pertussis toxin.
Insights
Guanosine triphosphate (GTP gamma S) addition solubilizes major proteins like myosin and actin from rabbit neutrophil membranes. This nucleotide-driven effect is calcium-independent and not affected by pertussis toxin pretreatment.
Area of Science:
- Cellular biology
- Biochemistry
- Molecular signaling
Background:
- Neutrophil membranes contain proteins crucial for cellular function.
- Guanosine triphosphate (GTP) binding proteins are involved in signal transduction pathways.
- Understanding protein-membrane interactions is key to cellular processes.
Purpose of the Study:
- To investigate the effect of guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) on protein solubilization from rabbit neutrophil membranes.
- To identify the major proteins affected by GTP gamma S.
- To compare the potency of different nucleotides in inducing protein solubilization.
Main Methods:
- Isolation of membrane fractions from rabbit peritoneal neutrophils.
- Incubation with guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) and various other nucleotides.
- Analysis of solubilized proteins using molecular weight markers (e.g., myosin and actin).
- Testing the role of calcium and pertussis toxin pretreatment.
Main Results:
- GTP gamma S addition led to the solubilization of several membrane proteins.
- The primary solubilized proteins were identified as myosin (180 kDa) and actin (43 kDa).
- The half-maximum effective concentration for GTP gamma S was 70 microM.
- Nucleotide potency order was GTP gamma S > GTP > ATP > GDP, GMP, cGMP, cAMP.
- The effect was independent of calcium and unaffected by pertussis toxin.
Conclusions:
- GTP gamma S effectively solubilizes myosin and actin from neutrophil membranes.
- This process is mediated by nucleotide binding and is independent of calcium.
- The findings suggest a role for GTP-dependent mechanisms in regulating cytoskeletal protein association with the neutrophil membrane.