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Updated: Jan 31, 2026

Analysis of HBV-Specific CD4 T-cell Responses and Identification of HLA-DR-Restricted CD4 T-Cell Epitopes Based on a Peptide Matrix
Published on: October 20, 2021
Type II PtdIns 4-kinase β associates with CD4-p56lck complex and is involved in CD4 receptor signaling
Ranjeet Kumar Sinha1, Naveen Bojjireddy, Deepak Kanojia
1Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400076, India, ranjeet@scripps.edu.
Abstract:
Type II phosphatidylinositol (PtdIns) 4-kinases are involved in the synthesis of PtdIns 4-phosphates and modulate various cell functions like, intracellular signaling, cytoskeletal rearrangements, vesicular trafficking, and pathogen invasion. In CD3 receptor activated T cells, a type II PtdIns 4-kinase β is recruited to CD3 receptor zeta and plays a role in intracellular calcium release and probably in actin cytoskeleton reorganization. T cell receptor mediated activation is supported by CD4 receptor. The role of type II PtdIns 4-kinase β in CD4 receptor-mediated signaling was addressed in the present manuscript. Crosslinking of CD4 receptors with monoclonal antibodies showed an increase in CD4-associated PtdIns 4-kinase activity and requires p56(lck) activity. Biochemical characterization suggests that it belongs to type II PtdIns 4-kinase family. shRNA mediated knockdown of type II PtdIns 4-kinase β showed abrogation of CD4 receptor induced intracellular calcium release. These results suggest that type II PtdIns 4-kinase β plays an integral part in CD4 receptor-mediated signaling.
Insights
Type II phosphatidylinositol 4-kinase beta is crucial for CD4 receptor signaling in T cells. It regulates intracellular calcium release, impacting T cell activation pathways.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Type II phosphatidylinositol (PtdIns) 4-kinases synthesize PtdIns 4-phosphates, regulating cell functions including signaling and trafficking.
- PtdIns 4-kinase beta is known to associate with the CD3 receptor in T cells, influencing calcium release and actin dynamics.
Purpose of the Study:
- To investigate the role of type II PtdIns 4-kinase beta in CD4 receptor-mediated signaling pathways within T cells.
Main Methods:
- Stimulation of CD4 receptors using monoclonal antibodies to assess associated PtdIns 4-kinase activity.
- Biochemical characterization of the enzyme involved in CD4 signaling.
- siRNA-mediated knockdown of type II PtdIns 4-kinase beta to evaluate its functional impact.
Main Results:
- CD4 receptor crosslinking significantly increased CD4-associated PtdIns 4-kinase activity, dependent on p56(lck).
- Biochemical analysis confirmed the enzyme belongs to the type II PtdIns 4-kinase family.
- Knockdown of type II PtdIns 4-kinase beta abrogated CD4 receptor-induced intracellular calcium release.
Conclusions:
- Type II PtdIns 4-kinase beta is a key component of CD4 receptor-mediated signaling.
- This enzyme plays an integral role in regulating intracellular calcium release downstream of CD4 activation.
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