Abstract
We have developed a genetic system, called degrakine, that specifically and stably inactivates chemokine receptors (CKR) by redirecting the ability of the HIV-1 protein, Vpu, to degrade CD4 in the endoplasmic reticulum (ER) via the host proteasome machinery. To harness Vpu's proteolytic targeting capability to degrade new receptors, we fused a chemokine with the C terminal region of Vpu. The fusion protein, or degrakine, accumulates in the ER, trapping and functionally inactivating its target CKR. We have demonstrated that degrakines based on SDF-1 (CXCL12), MDC (CCL22) and RANTES (CCL5) specifically inactivate their respective receptor functions. Using a retroviral vector expressing the SDF-1 degrakine, we have established that CXCR4 is required for the homing of hematopoietic stem/progenitor cells (HSPC) to the bone marrow immediately after transplantation. Thus the degrakine provides an effective genetic tool to dissect receptor functions in a number of biological systems in vitro and in vivo.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Cells, Cultured
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Chemokines / administration & dosage
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Chemokines / genetics
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Chemokines / immunology*
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Chemokines / metabolism*
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Drug Delivery Systems / methods*
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Endoplasmic Reticulum / immunology
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Endoplasmic Reticulum / metabolism
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Gene Targeting / methods*
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Human Immunodeficiency Virus Proteins
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Humans
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Mice
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Osteitis / immunology
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Osteitis / metabolism
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Protein Engineering / methods
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Receptors, Chemokine / immunology*
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Receptors, Chemokine / metabolism*
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Recombinant Fusion Proteins / administration & dosage
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Recombinant Fusion Proteins / immunology
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Recombinant Fusion Proteins / metabolism
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Viral Regulatory and Accessory Proteins / administration & dosage
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Viral Regulatory and Accessory Proteins / genetics
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Viral Regulatory and Accessory Proteins / immunology*
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Viral Regulatory and Accessory Proteins / metabolism*
Substances
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Chemokines
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Human Immunodeficiency Virus Proteins
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Receptors, Chemokine
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Recombinant Fusion Proteins
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Viral Regulatory and Accessory Proteins
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vpu protein, Human immunodeficiency virus 1