Prolactin inducible protein in cancer, fertility and immunoregulation: structure, function and its clinical implications.
Prolactin inducible protein (PIP) is a 17- kDa single polypeptide chain, known by various names due to its versatile nature and function in human reproductive and immunological systems. It is expressed in several exocrine tissues such as the lacrimal, salivary, and sweat glands. Its expression is up regulated by prolactin and androgens, and estrogens down regulate it. Due to its over-expression in metastatic breast and prostate cancer, presently PIP is considered as a prognostic biomarker. Moreover, its aspartyl-proteinase nature suggests its role in tumor progression. PIP has unique features because it is small in size and plays multiple important functions. Its ability to bind potentially with CD4-T cell receptor, immunoglobulin G (IgG), actin, zinc alpha2-glycoprotein (ZAG), fibronectin and enamel pellicle, reveals its important biological functions. This is the first comprehensive review on the structure and functional analysis of PIP and its clinical applications.
Hassan
Md I
MI
Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India.
Waheed
A
A
Yadav
S
S
Singh
T P
TP
Ahmad
F
F
D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018450:Disease Progression; D005298:Fertility / Q000502:physiology*; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D055633:Immune System Phenomena / Q000502:physiology*; D026901:Membrane Transport Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000503:physiopathology*; D011388:Prolactin / Q000378:metabolism; D011487:Protein Conformation; D016415:Sequence Alignment
D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D006023:Glycoproteins; D026901:Membrane Transport Proteins; C488892:PIP protein, human; D011388:Prolactin