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Related Concept Videos

Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
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The JAK-STAT Signaling Pathway

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Overview of Secretory Vesicles

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Identification of the Source of Secreted Proteins in the Kidney by Brefeldin A Injection
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Published on: November 10, 2021

Secreted protein kinases.

Vincent S Tagliabracci1, Lorenzo A Pinna, Jack E Dixon

  • 1Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.

Trends in Biochemical Sciences
|January 2, 2013
PubMed
Summary
This summary is machine-generated.

Researchers discovered a new family of secreted protein kinases, including Fam20C, that phosphorylate extracellular proteins like casein. This finding solves a 130-year-old mystery and offers insights into biomineralization disorders.

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Last Updated: May 15, 2026

Identification of the Source of Secreted Proteins in the Kidney by Brefeldin A Injection
10:15

Identification of the Source of Secreted Proteins in the Kidney by Brefeldin A Injection

Published on: November 10, 2021

Assaying Protein Kinase Activity with Radiolabeled ATP
08:05

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Published on: May 26, 2017

Identification of Kinase-substrate Pairs Using High Throughput Screening
11:13

Identification of Kinase-substrate Pairs Using High Throughput Screening

Published on: August 29, 2015

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Background:

  • Protein kinases are crucial regulators of cellular processes and represent a large gene family.
  • The first phosphoprotein, casein, was identified 130 years ago, but the kinase responsible remained unknown.
  • Extracellular protein phosphorylation was poorly understood due to the lack of identified secreted kinases.

Purpose of the Study:

  • To identify the kinase responsible for phosphorylating secreted proteins, specifically casein.
  • To characterize the novel family of secreted protein kinases.
  • To elucidate the mechanism and significance of extracellular protein phosphorylation.

Main Methods:

  • Biochemical assays to detect kinase activity in secreted fractions.
  • Protein identification and sequencing to discover novel kinases.
  • In vitro phosphorylation assays using purified proteins and synthetic substrates.
  • Analysis of the Ser-x-Glu/pSer motif in known and novel substrates.

Main Results:

  • Discovery of a novel family of atypical secreted protein kinases.
  • Identification of Fam20C as the archetypical member of this family.
  • Demonstration that Fam20C phosphorylates secreted proteins, including casein, at specific motifs (Ser-x-Glu/pSer).
  • Evidence that these kinases are responsible for a significant portion of extracellular protein phosphorylation.

Conclusions:

  • The discovery of secreted protein kinases, particularly Fam20C, resolves a long-standing mystery in protein biochemistry.
  • This finding provides a new understanding of extracellular protein modification.
  • The identified kinases and their substrates are implicated in human disorders, especially those related to biomineralization.