Limits...
Assessing the Functional Role of Leptin in Energy Homeostasis and the Stress Response in Vertebrates

View Article: PubMed Central - PubMed

ABSTRACT

Leptin is a pleiotropic hormone that plays a critical role in regulating appetite, energy metabolism, growth, stress, and immune function across vertebrate groups. In mammals, it has been classically described as an adipostat, relaying information regarding energy status to the brain. While retaining poor sequence conservation with mammalian leptins, teleostean leptins elicit a number of similar regulatory properties, although current evidence suggests that it does not function as an adipostat in this group of vertebrates. Teleostean leptin also exhibits functionally divergent properties, however, possibly playing a role in glucoregulation similar to what is observed in lizards. Further, leptin has been recently implicated as a mediator of immune function and the endocrine stress response in teleosts. Here, we provide a review of leptin physiology in vertebrates, with a particular focus on its actions and regulatory properties in the context of stress and the regulation of energy homeostasis.

No MeSH data available.


Alignment of teleost leptin A (LepA) with the leptin homologs from other vertebrate classes. Accession numbers: tilapia LepA, AHL37667.1; zebrafish LepA, NP_001025357.2; salmon LepA, ACZ02412.1; fugu, NP_001027897.1; Xenopus, NP_001089183.1; falcon, NP_001298279.1; mouse, NP_032519.1; human, NP_000221.1. Shaded areas represent the conserved cysteine residues required for the formation of the disulfide bridge. The four alpha-helices are indicated by dashed lines within the parentheses.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5384446&req=5

Figure 1: Alignment of teleost leptin A (LepA) with the leptin homologs from other vertebrate classes. Accession numbers: tilapia LepA, AHL37667.1; zebrafish LepA, NP_001025357.2; salmon LepA, ACZ02412.1; fugu, NP_001027897.1; Xenopus, NP_001089183.1; falcon, NP_001298279.1; mouse, NP_032519.1; human, NP_000221.1. Shaded areas represent the conserved cysteine residues required for the formation of the disulfide bridge. The four alpha-helices are indicated by dashed lines within the parentheses.

Mentions: Leptin was first cloned in the mouse by Zhang et al. (1) and has since been identified in all extant vertebrate groups examined to date. Following the discovery of leptin in the mouse, orthologs were identified in several other mammalian species (4); however, attempts to isolate a putative leptin sequence in non-mammalian vertebrates were largely unsuccessful. It was not until 2005, over a decade after its discovery in mammals, that a leptin homolog was cloned in a non-mammalian species, the Japanese pufferfish [Takifugu rubripes (5)]. This delay was due to the low amino acid identity (often less than 30%) between vertebrate leptin sequences (6) (Figure 1). The deduced primary structure of the pufferfish leptin (pLep) shared only 13.2% identity with human leptin; however, three-dimensional modeling suggested a strong conservation of tertiary structure with mammalian leptins, as pLep also possesses four α-helices (5). Further, the amino acid sequence of pLep contained two cysteine residues to form the disulfide bridge between α-helices C and D, a highly conserved element of vertebrate leptins (5).


Assessing the Functional Role of Leptin in Energy Homeostasis and the Stress Response in Vertebrates
Alignment of teleost leptin A (LepA) with the leptin homologs from other vertebrate classes. Accession numbers: tilapia LepA, AHL37667.1; zebrafish LepA, NP_001025357.2; salmon LepA, ACZ02412.1; fugu, NP_001027897.1; Xenopus, NP_001089183.1; falcon, NP_001298279.1; mouse, NP_032519.1; human, NP_000221.1. Shaded areas represent the conserved cysteine residues required for the formation of the disulfide bridge. The four alpha-helices are indicated by dashed lines within the parentheses.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384446&req=5

Figure 1: Alignment of teleost leptin A (LepA) with the leptin homologs from other vertebrate classes. Accession numbers: tilapia LepA, AHL37667.1; zebrafish LepA, NP_001025357.2; salmon LepA, ACZ02412.1; fugu, NP_001027897.1; Xenopus, NP_001089183.1; falcon, NP_001298279.1; mouse, NP_032519.1; human, NP_000221.1. Shaded areas represent the conserved cysteine residues required for the formation of the disulfide bridge. The four alpha-helices are indicated by dashed lines within the parentheses.
Mentions: Leptin was first cloned in the mouse by Zhang et al. (1) and has since been identified in all extant vertebrate groups examined to date. Following the discovery of leptin in the mouse, orthologs were identified in several other mammalian species (4); however, attempts to isolate a putative leptin sequence in non-mammalian vertebrates were largely unsuccessful. It was not until 2005, over a decade after its discovery in mammals, that a leptin homolog was cloned in a non-mammalian species, the Japanese pufferfish [Takifugu rubripes (5)]. This delay was due to the low amino acid identity (often less than 30%) between vertebrate leptin sequences (6) (Figure 1). The deduced primary structure of the pufferfish leptin (pLep) shared only 13.2% identity with human leptin; however, three-dimensional modeling suggested a strong conservation of tertiary structure with mammalian leptins, as pLep also possesses four α-helices (5). Further, the amino acid sequence of pLep contained two cysteine residues to form the disulfide bridge between α-helices C and D, a highly conserved element of vertebrate leptins (5).

View Article: PubMed Central - PubMed

ABSTRACT

Leptin is a pleiotropic hormone that plays a critical role in regulating appetite, energy metabolism, growth, stress, and immune function across vertebrate groups. In mammals, it has been classically described as an adipostat, relaying information regarding energy status to the brain. While retaining poor sequence conservation with mammalian leptins, teleostean leptins elicit a number of similar regulatory properties, although current evidence suggests that it does not function as an adipostat in this group of vertebrates. Teleostean leptin also exhibits functionally divergent properties, however, possibly playing a role in glucoregulation similar to what is observed in lizards. Further, leptin has been recently implicated as a mediator of immune function and the endocrine stress response in teleosts. Here, we provide a review of leptin physiology in vertebrates, with a particular focus on its actions and regulatory properties in the context of stress and the regulation of energy homeostasis.

No MeSH data available.