Placental lactogen-I variant utilizes the prolactin receptor signaling pathway.
Placenta lactogen-I variant (PL-Iv) is a member of a family of proteins expressed by the rat placenta with characteristics similar to prolactin (PRL). In this report, we present the molecular cloning, chromosomal localization, and heterologous expression of PL-Iv. Nucleotide sequence analysis of the PL-Iv cDNA clone predicted a precursor protein of 223 amino acids, including a 28-amino acid signal sequence. The PL-Iv gene was localized to chromosome 17 of the rat genome, which also carries other members of the PRL gene family. PL-Iv heterologously expressed in Chinese Hamster ovary (CHO) cells exhibited similar immunoreactive and electrophoretic characteristics with PL-Iv produced by the rat placenta. N-terminal sequencing verified the identity and purity of the recombinant PL-Iv species and the site of cleavage of the signal peptide from the mature secreted PL-Iv species. Recombinant PL-Iv was shown to bind to ovarian and liver PRL receptors, stimulate the proliferation of Nb2 lymphoma cells, and activate Jak2. Each of these actions is consistent with PL-Iv utilizing the PRL receptor signal transduction pathway.
Cohick
C B
CB
Department of Physiology, University of Kansas Medical Center, Kansas City 66160-7401, USA.
Dai
G
G
Xu
L
L
Deb
S
S
Kamei
T
T
Levan
G
G
Szpirer
C
C
Szpirer
J
J
Kwok
S C
SC
Soares
M J
MJ
D000818:Animals; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D015870:Gene Expression; D014644:Genetic Variation; D010928:Placental Lactogen / Q000235:genetics* / Q000378:metabolism*; D011247:Pregnancy; D021382:Protein Sorting Signals / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011981:Receptors, Prolactin / Q000378:metabolism*; D015398:Signal Transduction
D018076:DNA, Complementary; D021382:Protein Sorting Signals; D011981:Receptors, Prolactin; C085699:placental lactogen I, rat; D010928:Placental Lactogen