Biology Reference
In-Depth Information
Fig. 6.1 Capacitation biological network. Actin polymerization (
red node
) interacts with
(
red arrows
) all cellular compartments
computational model, representing molecules involved in the postejaculatory mat-
uration of the male gamete and their interactions and taking into account different
intracellular locations. Through this innovative approach, it was possible to high-
light how actin polymerization is the crucial node in the interconnection of various
subcellular compartments. This event appears to be related to all metabolically
active compartments in the sperm during capacitation (i.e., cytosol, membrane,
cytoskeleton, mitochondria, and acrosome). It is also interesting to note that the
only cellular compartment that has no relationship with actin polymerization is the
nucleus, which, in sperm, remains silent until the moment of fertilization. Thus, it is
clear that actin polymerization likely plays a role in the coordination between the
various metabolic pathways, harmonizing their operation. In the case of inhibition
of actin polymerization (in our work after treatment with CD), in fact, the individual
signal transduction pathways are normally activated, but the acquisition of
fertilizing power is compromised by their lack of coherence. The identification of
the cytoskeleton as a factor involved in the inside-out signaling of sperm appears to
be important. First, it is in line with recent observations made in other cellular
models (Shafrir et al.
2000
), ascribing to this structure a leading role in the
evolution and implementation of cellular signaling, independent on its mechanical
function. It could then reveal new analytical and descriptive approaches for the
physiology of the male gamete. Finally, it could suggest new prognostic or thera-
peutic strategies in reproductive medicine.
