Related Experiment Video

Updated: Jul 15, 2026

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

Phosphorylation of steroid receptor coactivator-1. Identification of the phosphorylation sites and phosphorylation

B G Rowan1, N L Weigel, B W O'Malley

  • 1Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.

The Journal of Biological Chemistry
|February 8, 2000
PubMed

Insights

Steroid receptor coactivator-1 (SRC-1) phosphorylation sites were identified, revealing Erk-2 kinase involvement. This uncovers a key regulatory mechanism for steroid/nuclear receptor activity.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Biochemistry

Background:

  • Steroid receptor coactivator-1 (SRC-1) amplifies steroid/nuclear receptor activity.
  • Understanding SRC-1 regulation by cellular signaling pathways is crucial.

Purpose of the Study:

  • To identify the major phosphorylation sites of SRC-1.
  • To investigate the role of mitogen-activated protein kinase (MAPK) pathways in SRC-1 regulation.

Main Methods:

  • In vivo labeling with [(32)P]H(3)PO(4).
  • Modified manual Edman degradation.
  • Phosphoamino acid analysis, endoproteinase digestion, and mutagenesis.

Main Results:

  • Seven phosphorylation sites identified: Ser372, Ser395, Ser517, Ser569, Ser1033, Thr1179, and Ser1185.
  • Erk-1 and Erk-2 (MAPK family) consensus sequences found at Ser395 and Thr1179.
  • Erk-2 directly phosphorylated Thr1179, Ser1185, and Ser395 in vitro.
  • Epidermal growth factor enhanced SRC-1's role in progesterone receptor-mediated gene activation.

Conclusions:

  • Phosphorylation is a significant regulatory modification of SRC-1.
  • MAPK signaling pathways, particularly involving Erk-2, play a role in regulating SRC-1 function.
  • These findings provide a foundation for understanding how signaling pathways modulate SRC-1 and steroid/nuclear receptor action.

More Related Videos

Oligopeptide Competition Assay for Phosphorylation Site Determination09:16

Oligopeptide Competition Assay for Phosphorylation Site Determination

Published on: May 18, 2017

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

Related Concept Videos

Phosphorylation01:02

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Phosphorylation01:02

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...