Related Experiment Video
Updated: Jul 10, 2026
05:11
High-precision Electromagnetic Flowmeter with Empty Pipe Detection via Complex Programmable Logic Device-based Waveform Recognition
Published on: June 27, 2025
A flip-flop switch in polarity signaling
1Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.
Developmental Cell
|November 6, 2007
Summary
Budding yeast growth relies on Cdc42, a Rho GTPase. Its activity is controlled by GTPase-activating proteins (GAPs), which Saito et al. found are regulated by membrane phospholipid composition via flippases Lem3-Dnf1 and Lem3-Dnf2.
Area of Science:
- Cell biology
- Molecular biology
- Biochemistry
Background:
- The Rho GTPase Cdc42 is crucial for polarized cell growth in budding yeast.
- Temporal regulation of Cdc42 activity is mediated by its GTPase-activating proteins (GAPs).
Purpose of the Study:
- To investigate the regulatory mechanisms controlling Cdc42 GTPase-activating protein (GAP) activity in budding yeast.
Main Methods:
- Investigated the role of membrane phospholipid composition in regulating Cdc42 GAP activity.
- Utilized genetic and biochemical approaches to study the function of phospholipid flippases Lem3-Dnf1 and Lem3-Dnf2.
Main Results:
- Cdc42 GAP activity is directly modulated by the specific phospholipid environment of the bud-tip membrane.
- The phospholipid flippases Lem3-Dnf1 and Lem3-Dnf2 play a key role in controlling this membrane composition and, consequently, Cdc42 GAP activity.
Conclusions:
- Membrane phospholipid composition is a critical regulatory factor for Cdc42 GTPase-activating proteins.
- The Lem3-Dnf1/Lem3-Dnf2 flippase system provides temporal control over Cdc42 activity, essential for polarized growth in budding yeast.
Related Concept Videos
01:22Switching of BJT
Switching behavior in Bipolar Junction Transistors (BJTs) is a fundamental aspect utilized in various electronic circuits, particularly for digital logic applications like switches and amplifiers. In a typical switching circuit, a BJT alternates between cut-off and saturation modes, corresponding to the "off" and "on" states, respectively, thus behaving like an ideal switch.
Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are reverse-biased. The...
Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are reverse-biased. The...
01:14Diode: Reverse bias
A diode is reverse-biased when the positive terminal of an external voltage source is connected to the n-type material and the negative terminal to the p-type material. This configuration opposes the natural direction of current flow through the diode, effectively increasing the width of the depletion region and the barrier potential. The reverse bias condition produces a minimal leakage current, primarily due to minority charge carriers. This leakage becomes significant when the reverse...
01:22Bipolar Junction Transistor
Bipolar Junction Transistors (BJTs) are essential elements in electronic circuits, playing a crucial role in the functionality of amplifiers, memories, and microprocessors. These transistors can be designed as NPN or PNP based on their doping patterns. They consist of three layers: the emitter, base, and collector. The configuration of these layers and their respective doping levels—with N-type or P-type impurities—define the transistor's type and its operational characteristics.
The structure...
The structure...
01:22Biasing of FET
Biasing a Junction Field Effect Transistor (JFET) is crucial for setting operational parameters and ensuring efficient functioning in electronic circuits. JFETs are characterized by using a single carrier type in N-channel or P-channel configurations, where the channel is surrounded by PN junctions. These junctions are central to the device's ability to control current flow.
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
01:22MOSFET: Enhancement Mode
Enhancement-mode MOSFETs are pivotal components in electronics, distinguished by their capacity to act as highly efficient switches. They are part of the larger family of metal-oxide Semiconductor Field-Effect Transistors (MOSFETs). They are available in two types: p-channel and n-channel, each tailored to specific polarity operations.
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no current...
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no current...
01:16Biasing of P-N Junction
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...