Brain Cells Have a Twist-Open Gate

first_img(Visited 16 times, 1 visits today)FacebookTwitterPinterestSave分享0 The structure of an important potassium-ion gate in the membrane of brain cells has been found to open like a camera iris.In Nature, Eitan Reuveny described a paper in the same issue by Whorton and MacKinnon that reveals how an important molecular gate named GIRK2 works in the membranes of brain cells.  These gates control the passage of potassium ions (K+) to the outside of the cell, a process that changes the electrical charge between inside and outside, allowing conduction of electrical signals.  His description, “Ion channel twists to open,” compares the twisting motion of the components to a camera iris: “The conformational changes that open the inner helical gate are comparable to the widening of a lens aperture by hand-rotating the aperture ring.”But whose hands rotate the ring?  The cylindrical channel that allows passage of K+ ions is surrounded by four complex proteins that lock into the cell membrane.  Activation of these “hands” by G-protein coupled receptors makes them turn the channel, opening it just a bit wider, but not enough, to allow the ions through.  From there, random perturbations may permit the ions to “burst” through the narrow opening as observed in living cells.  The channel also contains a “selectivity filter” to ensure only K+ ions can make it through.Reuveny began by explaining the importance of these channcels:Ion channels are the main units responsible for the electrical activity in our body. They constitute a large family of some 400 proteins in humans. A subfamily of these proteins consists of four GIRK channels, which specialize in converting chemical signals — mostly those of neurotransmitter molecules such as acetylcholine, dopamine, serotonin and adrenaline — into electrical ones in heart cells and neurons. They are therefore essential for controlling heart rate and the activity of neural circuits.Roderick MacKinnon received the Nobel Prize in Chemistry in 2003 for his work on ion channels (see “Wonders of the Salt Gate” 1/17/02, also 3/12/02, 5/29/02, 5/01/03).  This paper contributes to the “long-awaited crystal structure of the mammalian GIRK2 channel in complex with two subunits of a G protein (a dimer of the Gβ and Gγ subunits), providing information about their mechanism of opening,” Reuveny said.  Ion channels such as GIRK2 literally “pump” ions against the direction of osmosis in order to set up the voltage necessary for electrical transmission.It’s nice to see MacKinnon still at work uncovering the secrets of these cellular gates a decade after receiving his Nobel.  In the past 10 years, has he seen the light of the Darwinists?  Has he found evolution essential to explain how these exquisite molecular gates work?  Nope.  Neither MacKinnon or Reuveny even mentioned it.Thinking about the action of these gates in slow-motion is amazing enough.  Realize, though, that they act lightning-fast, allowing your heart rate to adjust and allowing chemicals and ions to speed through the brain at the speed of thought.  Just like in 2002, this is phenomenal evidence for intelligent design.last_img read more

Integrity In Your Pipeline

first_imgOne surefire way to miss your goals is to have a pipeline that lacks integrity. The lack of integrity isn’t intentional. No one is really lying about their pipeline. Mostly, there is just a lack of rigor around opportunities. Here are a few of the root causes that you need to remove if you want a pipeline you can believe.Bad Dates: No client will ever tell you that they need to close a deal on the last day of the month, the last day of a quarter, or the last day of the year. Those as “salespeople dates” used as a placeholder for the date by which they believe they can wrap up a deal. A client may, however, want to go live on the first day of a quarter or a year, in which case, their contract will likely need to be signed some time before, allowing time to get through the process.Too Old: Problems don’t age well, and neither do deals. The age of a deal can tell you whether you are looking at something you have a shot of winning. If the deal has been in the pipeline long enough to have its third birthday or has covered two Presidential elections, it’s not something you want to bet on in most cases.Bad Deals: If a deal should have been disqualified, it doesn’t belong in your pipeline. A fast “no” to bad deals is much better—and much healthier—than a slow “no” to those same deals.Wrong Stage: Some of the aging deals in your pipeline may become your client someday. You may have deals that look they have progressed to the point where your prospect will make a decision even when that decision is still far away. The optimism that causes one to believe they are going to win a deal might be well-founded. That said, just because you gave a prospect a proposal don’t mean they are prepared to sign a contract. If you skipped some of the commitments in this book, you may need to go backwards to go forward.A pipeline that lacks integrity can give you a false sense of confidence, causing you to believe that you are closing to your goals than you are. A bad number that is true is less damaging that a good number that is false. It can also prevent you from recognizing what you need to do to produce the results you want. Essential Reading! Get my first book: The Only Sale Guide You’ll Ever Need “The USA Today bestseller by the star sales speaker and author of The Sales Blog that reveals how all salespeople can attain huge sales success through strategies backed by extensive research and experience.” Buy Nowlast_img read more

VVIP chopper scam: ED summons M.P. CM’s nephew

first_imgThe Enforcement Directorate informed a Delhi court on Wednesday that it has summoned Ratul Puri, nephew of Madhya Pradesh Chief Minister Kamal Nath, for interrogation in a money laundering case related to the AgustaWestland VVIP chopper scam. ED told Special Judge Arvind Kumar that Mr. Puri, Chairman of Hindustan Powerprojects Pvt Ltd, was summoned for confronting him with Sushen Mohan Gupta, an arrested middleman in the case, whose custodial interrogation was on Wednesday extended by three more days by the court. Seeking the extension of Mr. Gupta’s custody, ED told the court that he was required to be confronted with various people including Mr. Puri in the case pertaining to the now scrapped ₹3,600 crore chopper deal. Mr. Puri, who was summoned to join the probe on Wednesday, denied having “any connection or involvement of any kind in defence or the case”.In a statement, his company said: “He would be fully cooperating with the ED investigation and provide any clarification or information as may be required.” Middleman’s statementAccording to ED sources, Mr. Puri’s name appeared in the statement recorded by middleman and Dubai-based businessman Rajeev Saxena, who recently turned approver in the case. ED’s special public prosecutors D.P. Singh and N.K. Matta also told the court that the agency wanted to identify one “RG”, in whose name entries of over ₹50 crore were made in Mr. Gupta’s diaries.“The custodial interrogation of Gupta is required as he is misguiding the probe by deliberately giving wrong explanation of abbreviations in his diaries wherein abbreviation ‘RG’ finds mention in many pages as well as pen drive data.“More than ₹50 crore shown to have been received from ‘RG’ between 2004 to 2016, whereas the ‘RG’ identified by Mr. Gupta, i.e., Rajat Gupta, had admitted to have cash transactions with Sushen from 2007 onwards and the same are being quantified,” the agency told the court. The agency submitted that Sushen said he only knew one ‘RG’ who was Rajat Gupta, whereas Rajat denied the transactions made in the name of RG and said he not the person being referred to.last_img read more