Newest definition of a cellular signal and description of the protein model of a cellular signal transduction see in the following paper:
Evidence of a new type of protein-protein interaction: desensitized actomyosin blocks Ca2+-sensitivity of the natural one. A possible model for an intracellular signalling system related to actin filaments.
V.V. Matveev, Institute of Cytology, Lab of Cell Physiology, Russian Academy of Sciences, 194064, St.Petersburg, Tikhoretsky Ave 4, Russia
ABSTRACT
Actin filaments are certainly believed to function as an intracellular signalling system; however, this is not confirmed by direct evidence. We used a two-layer actomyosin gel with a concentration gradient of the troponin-tropomyosin complex (TT-complex, Ca2+-sensitive system) between the two layers. To prepare one layer of the system, natural actomyosin (nAM) rich in TT-complex was used. To prepare the second layer, we used desensitized actomyosin (dAM) without the complex. All experiments were made in medium with a low ionic strength. Two phenomena were observed: (1) dAM blocks Ca2+-sensitivity of nAM when the dAM weight portion in the system (as well as in mixed nAM+dAM suspension) reaches 40% and more; further increase of the dAM portion does not affect the Ca2+-sensitivity; (2) it was electrophoretically shown that a rapid diffusion of the TT-complex from nAM gel into the dAM gel took place. The apparent diffusion coefficient for the TT-complex in dAM gel is about (1-4)x10-4 cm2/sec, i.e. three orders higher than the same values for protein diffusion in water.
Physiological Chemistry Physics & Medical NMR, 32: 167-179, 2000
The full text of the article is available on the homepage: http://actomyosin.narod.ru
The author will be grateful to all for discussion and critical remarks to my work.
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