Myosin heavy chain interactions

Multiple cellular effects of D-fructose-albumin imply the existence of specific cellular receptors for this molecule, and a search for such receptors has identified so far a number of such sites on monocytes, peritoneal and alveolar macrophages, endothelial cells, and fibroblasts. Cell-membrane proteins that may interact with D-fructose-albumin through its A/ -D-fiuctose-L-lysine epitopes include nucleolin, myosin heavy chain, and calnexin. ... 

SM) a-actin, myosin heavy chain and caldesmon. In attempts to engineer blood vessels using bioreactor systems, interactions between ECs and SMCs (e.g., EC adhesion to and lining of the inner lumen in contact with cultured SMCs) have improved by subjecting the system to proper mechanical stim-uh. In addition, cyclic strain has been shown to induce stem cell differentiation in SMCs (Park, 2007). 

Hiratsuka, T. (1987) Nucleotide-induced change in the interaction between the 20- and 26-kilodalton heavy-chain segments of myosin adenosine triphosphatase revealed by chemical cross-linking via the reactive thiol SH2. Biochemistry 26, 3168. 

Labbe, J.R, Mornet, D., Roseau, G., and Kassab, R. (1982) Cross-linking of F-actin to skeletal muscle myosin subfragment 1 with bis(imido esters) Further evidence for the interaction of myosin-head heavy chain with an actin dimer. Biochemistry 21, 6897-6902. 

S100A4, like some other S100 proteins, is able to relocate upon cellular stimulation, allowing its interaction with different partner proteins in a spatial and temporal manner. These include liprin (31, a member of the family of LAR transmembrane phosphatase -interacting proteins (Kriajevska et al., 2002), annexin II (Semov et al., 2005), p53 (Grigorian et al., 2001), methionine aminopep-tidase 2 (Endo et al., 2002), or myosin-IIA heavy chain (Li and Bresnick, 2006). 

The characteristic (consensus) sequence ofP-loops (the Walker A motif Walker et al., 1982) is Gly-x-x-x-x-Gly-Lys-Thr/Ser (the region in red in Fig. 5) this sequence is often used in bioinformatic searches to identify proteins related to this family. Each myosin and kinesin has a single P-loop. For example, Dictyostelium myosin II has the sequence as in Fig. 5 (179) G-E-S-G-A-G-K-T (186). On the other hand, dynein, with a heavy chain that partly forms a ringlike core complex of six AAA+ domains, has P-loop motifs in the first four of these domains (e.g., G-P-A-G-P-G-K-T). There may be a complex series of interactions between these various sites to generate movement, but the P-loop in the third domain has been shown to be essential for dynein motor function (Silvanovich et al., 2003). 

Fig. 4. A model for the control of PBX subcellular localization. Non-muscle myosin II heavy chain B (myosin) stabilizes a conformation of PBX that masks the two NLS in the homeodomain (HD). Interaction of MEIS/PREP (MEIS) with the PBX N-terminus (PBX) induces a conformational change that exposes the NLS, allowing contact with the nuclear import machinery (import). Dissociation of MEIS from PBX within the nucleus unmasks one or more NES and leads to interaction with the CRM1-dependent nuclear export apparatus.

On the other hand, it has been suggested, based on immunopre-cipitation reactions, that CCT might interact with a broad range (accounting for 9-15%) of newly synthesized eukaryotic proteins (Feldman and Frydman, 2000 McCallum et al., 2000 Thulasiraman et al., 1999). There is also evidence that some proteins other than actins and tubulins fold via interaction with CCT. These include G -transducin (Farr etal, 1997), cyclinE (Won etal., 1998), and the von Hippel-Landau tumor suppressor protein VHL (Feldman et al., 1999). Moreover, translation in vitro of myosin heavy and light chains has identified an intermediate in the biogenesis of the heavy meromyosin subunit (HMM) of skeletal muscle myosin that contains all three myosin subunits and CCT, from which partially folded HMM can be released in an ATP-dependent reaction. Other as yet unknown cytosolic protein(s) are also apparently required for the completion of the myosin folding reaction (Srikakulam and Winkelmann, 1999). 

However, since myosin is the native substrate, it is important to consider only those phosphatases that can dephosphorylate myosin. When LC20 associates with the heavy chains, its availability for dephosphorylation by many MLCP decreases dramatically. Furthermore, subunit composition of the phosphatase might also hinder interaction with intact myosin (Pato and Kerc, 1986). Besides this primary requirement that the MLCP should be effective with the native substrate, binding studies with phosphorylated and dephosphorylated myosins are also useful to indicate interaction with myosin (Sellers and Pato,... 

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