Correlations of protein networks with physiological parameters
Correlation coefficient was determined between organismal measurements
versus protein FC. Correlated variables included blood osmolality,
condition factor (K), experimental salinity, and time at salinity above
65g/kg (~2X SW). Of these variables, blood osmolality
difference from treatment to control was correlated with protein
abundance with r2>0.9 for 446 proteins,
with 280 of these proteins being significantly regulated in at least one
treatment (Supplementary Table 2). Condition factor difference was
correlated with r2>0.9 for 212 proteins,
of which 125 were significantly regulated in at least one treatment.
Experimental salinity was correlated with an
r2>0.9 for only 16 proteins (6
significant) and time above 65g/kg was correlated with an
r2>0.9 for 51 proteins (20 sig). Proteins
with high blood osmolality correlation were analyzed using the STRING
database, revealing one network with greater than three nodes which
consisted of proteins involved in cell adhesion, ECM organization, and
junctional complexes (Figure 5C). The STRING database annotated six of
these proteins as associated with the serpin protein domain (SERine
Protease Inhibitor), including serine protease inhibitor A3K,
α-1-antitrypsin, protein Z-dependent protease inhibitor,
angiotensinogen, complement factor D, and heparin cofactor 2. Four of
the proteins were found in the “focal adhesion” KEGG molecular
pathway, including α-actinin-1 X3, fibronectin, and two integrins (α-1
and α-6 X1). All proteins had negative slopes (decreasing FC with
increasing blood osmolality) except for catenin δ-1 X3 and tropomyosin β
X2, and the later was also found in a pejus range network.