Insights from the sequence similarity of Zika virus proteins with the Human nerve proteins

Massive peptide sharing between the Zika virus polyprotein and host tissue proteins could elicit significant host-pathogen interactions and cross-reactions leading to autoimmune diseases. This study found similarities in the Zika V proteins and human nerve tissue proteins. 63 human nerve proteins were screened for similarities with the Zika V of which Neuromodulin, Nestin, Galanin, Bombesin, Calcium-binding protein were found to have similarities to the Zika V poly protein C at different sequence regions. These sequence similarities could be significant in regulating pathogenic interactions/autoimmunity, as Polyprotein C is known to be a virulent factor.

Protein phosphorylation pattern in the immune cells of leprosy affected individuals

BACKGROUND

Leprosy is an infectious disease in which the susceptibility to the pathogen Mycobacterium leprae and the clinical manifestations are attributed to host immune cell response. Receptor mediated events and signalling in the immune cells are mediated by protein phosphorylation. The main signalling pathways and protein kinases known to be involved in the regulation of immune cells are cAMP dependent kinases, calcium/calmodulin dependent kinases, protein kinase C and mitogen activated protein kinases. The cumulative consequence of alterations in signalling pathways can be evaluated by intrinsic cellular protein phosphorylation by gamma-P32 ATP. The present study was designed to assess the protein phosphorylation in the immune cells of leprosy patients as compared with normal individuals.

METHODOLOGY

Lymphocyte protein phosphorylation was conducted in 15 leprosy patients and 9 normal individuals. Protein phosphorylation of lymphocytes was carried out in the presence/absence of protein kinase modulators. The phosphorylation patterns were documented and analysed consequent to SDS-PAGE, staining, destaining, drying and autoradiography.

RESULTS

The major phosphorylated proteins in lymphocytes were of molecular weights 20-22, 24-29, 30-35, 43, 46-50 and 66-68 kDa. In general, the major phosphorylated proteins were similar in the controls and in the patients. The phosphorylatability of these proteins varied with different modulators. Variations in the phosphorylation pattern were observed in 25% of the leprosy patients where there was a decrease of the 66 kDa protein and a decrease of 20-22 kDa protein phosphorylation.

CONCLUSION

The observed alterations in the protein phosphorylation pattern could be due to alteration in kinases and/or their substrates or due to the effect of M. leprae on immune cells.

Mycobacterium leprae binds to a 25-kDa phosphorylated glycoprotein of human peripheral nerve

Mycobacterium leprae, the causative agent of leprosy, specifically invades and destroys the peripheral nerve, which results in the main clinical manifestation of the disease. Little is known about the bacteria-nerve protein interaction. We show in the present work that M leprae binds to a 25 kDa glycoprotein from human peripheral nerve. This protein is phosphorylatable and it binds to lectins which have alpha-mannose specificity. This M leprae-protein interaction could be of importance in the pathogenesis of leprosy.

M. leprae binds to a 28-30-kDa phosphorylated glycoprotein of rat peripheral nerve

To understand Mycobacterium leprae-peripheral nerve interaction, we have investigated the binding of M. leprae to rat peripheral nerve proteins in an in vitro model using 32P-phosphorylated proteins of the peripheral nerve. Intact M. leprae binds to a major phosphorylated protein of 28-30 kDa and, to a minor extent, to a few proteins of molecular weight 45-55 kDa. This binding was more specific for M. leprae since only insignificant binding was observed with other bacteria, such as M. bovis or Escherichia coli. M. leprae did not show binding to several phosphorylated proteins of the rat brain. The 28-30-kDa binding protein of the rat peripheral nerve was found to be a glycoprotein by concanavalin A-Sepharose column chromatography.

Protein phosphorylation in human peripheral nerve: altered phosphorylation of a 25-kDa glycoprotein in leprosy

Protein phosphorylation in a low speed supernatant of human peripheral nerve (tibial and sural) homogenate was investigated. The major phosphorylated proteins had molecular mass in the range of 70, 55, 45, and 25 kDa. Mg2+ or Mn2+ was essential for maximum phosphorylation although Zn2+, Co2+, and Ca2+ could partially support phosphorylation. External protein substrates casein and histone were also phosphorylated. The protein phosphatase inhibitor orthovanadate enhanced the phosphorylation of the 45 and 25 kDa proteins significantly. Concanavalin A-Sepharose chromatography of the phosphorylated peripheral nerve proteins showed that the 25 kDa protein was a glycoprotein. Protein phosphorylation of peripheral nerves from leprosy affected individuals was compared with normals. The phosphorylation of 25 kDa protein was decreased in most of the patients with leprosy.