The ubiquitously expressed transmembrane enzyme Na,K-ATPase(NKA)is vital in maintaining functionality of cells.The association of α-and β-subunits is believed to be essential for forming a functional enzyme.In the l...The ubiquitously expressed transmembrane enzyme Na,K-ATPase(NKA)is vital in maintaining functionality of cells.The association of α-and β-subunits is believed to be essential for forming a functional enzyme.In the large milkweed bug Oncopeltus fasciatus fourα1-paralogs and four β-subunits exist that can associate into NKA complexes.This diversity raises the question of possible tissue-specific distribution and function.While the α1-subunits are known to modulate cardenolide-resistance and ion-transport efficiency,the functional importance of the β-subunits needed further investigation.We here characterize all four different β-subunits at the cellular,tissue,and whole organismal scales.A knockdown of different β-subunits heavily interferes with molting success resulting in strongly hampered phenotypes.The failure of ecdysis might be related to disrupted septate junction(SJ)formation,also reflected in β2-suppression-induced alteration in tracheal morphology.Our data further suggest the existence of isolated β-subunits forming homomeric or β-heteromeric complexes.This possible standalone and structure-specific distribution of the β-subunits predicts further,yet unknown pump-independent functions.The different effects caused byβknockdowns highlight the importance of the various β-subunits to fulfill tissue-specific requirements.展开更多
文摘The ubiquitously expressed transmembrane enzyme Na,K-ATPase(NKA)is vital in maintaining functionality of cells.The association of α-and β-subunits is believed to be essential for forming a functional enzyme.In the large milkweed bug Oncopeltus fasciatus fourα1-paralogs and four β-subunits exist that can associate into NKA complexes.This diversity raises the question of possible tissue-specific distribution and function.While the α1-subunits are known to modulate cardenolide-resistance and ion-transport efficiency,the functional importance of the β-subunits needed further investigation.We here characterize all four different β-subunits at the cellular,tissue,and whole organismal scales.A knockdown of different β-subunits heavily interferes with molting success resulting in strongly hampered phenotypes.The failure of ecdysis might be related to disrupted septate junction(SJ)formation,also reflected in β2-suppression-induced alteration in tracheal morphology.Our data further suggest the existence of isolated β-subunits forming homomeric or β-heteromeric complexes.This possible standalone and structure-specific distribution of the β-subunits predicts further,yet unknown pump-independent functions.The different effects caused byβknockdowns highlight the importance of the various β-subunits to fulfill tissue-specific requirements.
