Biology Reference
In-Depth Information
triggers a self-assembling process of about a dozen proteins (called signal trans-
ducing proteins known as MAPKKK, MAPKK, MAPK, STAT, JAK, etc.)
(Fig.
12.35
), driven by free-energy releasing phosphorylation-dephosphorylation
reactions catalyzed by ubiquitous (about 100 different kinds!) proteins called
kinases and phosphoprotein phosphatases present inside the cell. The biological
function of a signal transduction cascade, viewed as a SOWAWN machine, is to
turn on or off a target gene (related to V
O
in Eq. 5.63) under complex intracellular
environmental conditions (related to V
E
) by increasing the complexity of the
internal state of the cascade (indicated by V
M
).
As was suggested for the blood coagulation system, the components of a signal
transduction cascade do not exist inside the cell pre-assembled (most likely to
prevent cellular jam up) but are distributed randomly throughout the cell volume
and are programmed to assemble wherever and whenever needs arise inside the cell.
It is clear that SOWAWN machines are examples of what Prigogine called
“dissipative structures” (Prigogine 1977, 1980) and share common characteristics
with what Norris et al. refer to as “hyperstructures” (Norris et al 1999), what
Hartwell et al. (1999) called “modules,” and what I referred to as “IDSs” (intracel-
lular dissipative structures) (Ji 1991, pp. 69-73) (see Chap.
9
).
Machines and tools have been used by
Homo sapiens
probably for 2-3 millions
years. The concept of machines was generalized to include dynamic and transient
assemblies of interacting components (i.e.,
interactons
) only in the mid- to the
late-twentieth century, here called SOWAWN machines. And yet we now realize
that living systems may have been utilizing SOWAWN machines from their very
inception, i.e., for over 3.5 billion years!
Organisms can be viewed as networks of SOWAWN machines made out of
smaller SOWAWN machines. As already indicated, SOWAWN machines are
dissipative structures carrying both
free energy
and
genetic information
that are
essential for self-organizing into dynamic and transient systems to effectuate
specific functions including self-replication (see Eq.
2.56
). It should be pointed
out that, although SOWAWN machines are dissipative structures, not all dissipative
structures are SOWAWN machines. As accurately reflected in their acronym,
SOWAWN machines are dynamic material systems that have evolved to possess
the following characteristics:
1. Ability to self-organize (SO)
2. Ability to move/change in space and time (WAW) and
3. Ability to sense and meet the need (N) of themselves and others
2.4.4 Hyperstructures and SOWAWN Machines
There are concepts and theories published in the literature that are closely related to
SOWAWN machines, including
metabolons
(Srere 1987),
metabolic machines
(Holcome 1982; Ji 1991, pp. 44-49),
cytosociology
(Smith andWelch 1991),
modules
