ULTIMATE COMPUTING - Quantum Consciousness Studies

108 Cytoskeleton/Cytocomputer
channels at synaptic zones by specific cytoskeletal linkages. The MTL and
cytoskeleton also control the distribution of organelles, for example keeping the
endoplasmic reticulum from entering axons, restricting the Golgi apparatus to
perinuclear zones and keeping the synaptic bouton the right composition of
axoplasm. 4) The MTL can mediate embryological development or
morphogenesis through linkages with specific hormone receptors or tissue factors
resulting in variations in developmental patterns. 5) The MTL can transduce
chemical or mechanical work for intracellular transport and processes such as
axoplasmic transport and translocation of synaptic vesicles to release sites on the
presynaptic membrane. To Ellisman, the MTL regulates the rest of the
cytoskeleton and the cell at large. In his view, it is the dynamic ground substance
capable of intelligent behavior. One could argue, however, that MT regulate the
MTL. What is most significant is the question of how they communicate.
The most labile and transient of the cytoskeletal levels of organization, the
MTL is the current microfrontier of living material organization. The MTL is a
network within a network of cytoskeletal proteins which, in the case of the
nervous system, is a network within a network of neurons. In Chapter 8, a model
of information processing will be discussed in which the MTL represents standing
wave patterns of calcium coupled sol-gel states resulting from dynamic
excitations of the cytoskeleton. Coherent excitations in the cytoskeleton could
result in “holographic” standing waves which may be the bottom level of an
information hierarchy: “infoplasm.” An analog picture in which the MTL is both
paint and canvas could be the texture of consciousness.
5.4.2 The Cytomatrix
Others have viewed the fine structure of cytoplasm and described it in
different terms. Among these are Peter Satir (1984) of Albert Einstein University
whose work has focused on the protein makeup and functional organization of the
MTL, or “cytomatrix.” Satir sees a functional integration of the cytomatrix,
noting that protein-protein interactions have geometrical as well as biochemical
and biophysical consequences. Certain interactions occur only at the ends of
cytoskeletal polymers, others require or produce parallel arrangements of such
elements by interacting only with their lateral surfaces, and still others may
require orthogonal arrangements. In concert with centrioles, MTOC, and MT,
cytoplasmic structures appear and function where and when needed.
The primary building block of the cytomatrix/MTL appears to be actin, a
ubiquitous protein whose versatility describes the very nature of cytoplasm.
Interaction with a variety of other proteins (“actin-binding proteins”) unleash
actin’s full capabilities. When crosslinked by proteins such as fimbrin, actin can
form rigid bundles which provide structural support. When associated with
myosin (a “mechanoenzyme”), useful muscle-like contraction occurs. Also
important are proteins such as talin, spectrin, vinculin, ankyrin and fodrin which
connect the cytomatrix with membrane proteins, and calmodulin which mediates
effects of calcium ion fluxes on the cytomatrix.
Proteins such as alpha actinin, troponin, and filamin link actin in networks
which cause a gelatinous consistency to cytoplasm-a “gel” (Figure 5.20). In the
presence of calcium ions and actin fragmenting proteins such as villin and
gelsolin, the gel network liquefies to a solution-“sol.” Other actin regulatory
proteins include actin capping proteins, which stabilize polymerized actin and
promote a “gel” condition, and profilin which binds actin subunits, prevents
polymerization and maintains “sol” conditions. The layer of cytoplasm
immediately below cell membranes is in a continuous gel state (“cortical gel”),
but elsewhere dynamic transitions can occur. In the presence of myosin, actin gels