Análise dos efeitos dos antagonistas de calmodulina - w-7 e melitina - nas propriedades bioquímicas da miosina-v de cérebro

Abstract

Through cell biology new roles for the cytoskeleton are continually discovered. Revolution in knowledge has been made possible by the functional characterization of new proteins associated with it, genomic sequencing projects, and bioinformatics (SALMON, WAY, 1999). Microfilaments and microtubules, major components of the cytoskeleton, represent complex polymer systems that play essential roles during many cellular processes, including chromosomal segregation, cytokinesis, and motility (Moreau, Way, 1999). The superfamilies of kinesin and dynein motor proteins, associated with microtubules, act on cellular mechanisms such as organelle transport and mitosis (HIROKAWA et al., 1998). In addition to microtubule-dependent motors are unconventional actin-dependent myosins, which are involved in membrane traffic and organelle movement. SMALL et al. (1999) suggest that actin cytoskeleton plays the major role in determining cell form. However, its own reorganization is subject to modulation by extracellular interactions and microtubule-dependent activities. Thus, the interaction between microfilaments and microtubules is an important feature in cell adhesion and motility. Based on structural similarities, it is proposed that kinesins, myosins and G proteins have a common ancestor (VALE, MILL1GAN, 2000). The evolution of these molecular motors is shown in Figure 1. The functions of different myosin classes are investigated through biochemical, genetic, cytological analyzes, and localization studies suggest that class V myosins are related to organelle transport (MERMALL et al., 1998; BAKER, TITUS, 1998).