Related Experiment Video

Updated: Sep 29, 2026

Development and Application of Rapamycin-regulated Tyrosine Phosphatases
06:56

Development and Application of Rapamycin-regulated Tyrosine Phosphatases

Published on: September 6, 2024

The FKBP12-rapamycin-associated protein (FRAP) is a CLIP-170 kinase

Jae H Choi1, Paula G Bertram, Ryan Drenan

  • 1Myriad Proteonomics, Inc., Salt Lake City, UT 84116, USA.

EMBO Reports
|September 17, 2002
PubMed

Insights

FKBP12-rapamycin-associated protein (FRAP) interacts with microtubule-associated protein CLIP-170, phosphorylating it at specific sites. This phosphorylation by FRAP positively regulates CLIP-170

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Microtubule-associated proteins (MAPs) like CLIP-170 are crucial for microtubule organization and function.
  • CLIP-170 is a phosphoprotein, and its phosphorylation status is believed to regulate its interaction with microtubules.
  • The specific kinases responsible for CLIP-170 phosphorylation remain largely unidentified.

Purpose of the Study:

  • To investigate the interaction between CLIP-170 and potential kinases.
  • To identify the kinase(s) involved in CLIP-170 phosphorylation.
  • To determine the functional consequence of CLIP-170 phosphorylation on its microtubule-binding activity.

Main Methods:

  • Co-immunoprecipitation assays to detect protein interactions.
  • In vitro kinase assays to assess phosphorylation activity.
  • In vivo phosphorylation studies using rapamycin treatment.
  • Microtubule binding assays.

Main Results:

  • FKBP12-rapamycin-associated protein (FRAP, also known as mTOR/RAFT) was found to interact with CLIP-170.
  • CLIP-170 undergoes phosphorylation at both rapamycin-sensitive and -insensitive sites in vivo.
  • FRAP phosphorylates CLIP-170 in vitro at rapamycin-sensitive sites.
  • Rapamycin treatment inhibited the microtubule-binding ability of CLIP-170.

Conclusions:

  • Multiple kinases regulate CLIP-170 activity through phosphorylation.
  • FRAP is identified as a kinase that positively regulates CLIP-170's interaction with microtubules.
  • Phosphorylation by FRAP is a key mechanism controlling CLIP-170's function in microtubule dynamics.

More Related Videos

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells10:27

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

Related Concept Videos

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...
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...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
Membrane Asymmetry Regulating Transporters01:19

Membrane Asymmetry Regulating Transporters

Enzymes like flippase, floppase, and scramblase transfer phospholipids from one layer to another in the membrane, thereby affecting membrane asymmetry.
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Regulation of the Unfolded Protein Response01:31

Regulation of the Unfolded Protein Response

Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
Restarting Stalled Replication Forks02:37

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...