We analyzed the modulation by exogenous FXYD2 peptide and by endogenous protein kinases A and C, and Ca²⁺-calmodulin-dependent kinase, of gill (Na⁺, K⁺)-ATPase activity in the semi-terrestrial mangrove crab Ucides cordatus after 10-days acclimation to different salinities. Osmotic and ionic regulatory ability and gill (Na⁺, K⁺)-ATPase activity also were evaluated. (Na⁺, K⁺)-ATPase activity is stimulated by exogenous pig kidney FXYD2 peptide, while phosphorylation by endogenous protein kinases A and C and Ca²⁺/calmodulin-dependent kinase inhibits activity. Stimulation by FXYD2 and inhibition by protein kinase C and Ca²⁺/calmodulin-dependent kinase are salinity-dependent. This is the first demonstration of inhibitory phosphorylation of a crustacean (Na⁺, K⁺)-ATPase by Ca²⁺/calmodulin-dependent kinase. At low salinities, the (Na⁺, K⁺)-ATPase exhibited a single, low affinity ATP-binding site that showed Michaelis-Menten behavior. Above 18‰S, a second, cooperative, high affinity ATP-binding site appeared, corresponding to 10–20% of total (Na⁺, K⁺)-ATPase activity. Hemolymph osmolality was strongly hyper−/hypo-regulated in crabs acclimated at 2 to 35‰S. Cl⁻ was well hyper−/hypo-regulated although Na⁺ much less so, becoming isonatremic at elevated salinity. (Na⁺, K⁺)-ATPase activity was greatest in isosmotic crabs (26‰S), decreasing notably at 35‰S and also diminishing progressively from 18to 2‰S. Hyper-osmoregulation in U. cordatus showed little dependence on gill (Na⁺, K⁺)-ATPase activity, suggesting a role for other ion transporters. These findings reveal that the salinity acclimation response in U. cordatus consists of a suite of enzymatic and osmoregulatory adjustments that maintain its osmotic homeostasis in a challenging, mangrove forest environment.

我们分析了外源性FXYD2肽和内源性蛋白的调制激酶A和C，和Ca ²⁺ -钙调蛋白依赖性激酶鳃，（钠⁺，K ⁺）在半地面红树蟹-ATPase活性Ucides cordatus 10后天适应不同盐度。还评估了渗透和离子调节能力以及g （Na ⁺，K ⁺）-ATPase活性。（Na ⁺，K ⁺）-ATPase活性被外源猪肾FXYD2肽刺激，而内源蛋白激酶A和C和Ca ²⁺磷酸化/钙调蛋白依赖性激酶抑制活性。FXYD2刺激和蛋白激酶C和Ca ²⁺ /钙调蛋白依赖性激酶抑制是盐度依赖性的。这是Ca ²⁺ /钙调蛋白依赖性激酶抑制甲壳类（Na ⁺，K ⁺）-ATPase磷酸化的第一个证明。在低盐度下，（Na ⁺，K ⁺）-ATPase表现出一个单一的，低亲和力的ATP结合位点，该位点显示了Michaelis-Menten行为。高于18‰S时，出现了第二个合作的，高亲和力的ATP结合位点，占总数的10％至20％（Na ⁺，K ⁺）-ATP酶活性。在适应2至35‰S的螃蟹中，血淋巴重量摩尔渗透压浓度过高/过低调节。氯^-是公超支/防调节虽然钠⁺少得多，所以，成为在提高的盐度isonatremic。（Na ⁺，K ⁺）-ATPase活性在等渗螃蟹（26‰S）中最大，在35‰S时显着下降，从18‰至2‰S逐渐减小。脐带藻的渗透调节过度显示对little（Na ⁺，K ⁺）-ATPase活性的依赖性很小，这暗示了其他离子转运蛋白的作用。这些发现揭示了脐带藻的盐度适应性反应 由一系列酶促和渗透调节调节剂组成，可在充满挑战的红树林环境中保持其渗透稳态。