Volchuk BCH444 Jan. 9, 2014-Lecture #2(3) (1)

Volchuk BCH444 Jan. 9, 2014-Lecture #2(3) (1) - BCH444...

Info icon This preview shows pages 1–13. Sign up to view the full content.

1/13/2014 1 BCH444: Volchuk Lecture #2 1. Endoplasmic Reticulum Structure & Function Jan. 9 th , 2014 2. Phospholipid Biosynthesis & Transport
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

1/13/2014 2 Intracellular Transport Pathways: compartments of the secretory and endosomal systems Szul T , Sztul E Physiology 2011;26:348-364
Image of page 2
1/13/2014 3 ER   Structure   (Transmission   EM) RER : R ough E ndoplasmic R eticulum (contains areas of bound ribosomes on cytoplasmic membrane) t / b t i th i -secretory/membrane protein synthesis SER : S mooth E ndoplasmic R eticulum -phospholipid and cholesterol synthesis Transitional-ER : exit sites for transport vesicle formation
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

1/13/2014 4
Image of page 4
1/13/2014 5 Domains   of   the   ER   stabilized   by   membrane shaping   proteins (English   AR,   Voeltz   GA,   CSH   Perspect   Biol   2013;5:a013227)
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

1/13/2014 6 Main ER Functions - Site of secretory & membrane protein biosynthesis (RER) - Secretory & membrane protein folding - Initial site of secretory protein glycosylation - Calcium storage - Phospholipid biosynthesis (SER)
Image of page 6
1/13/2014 7 How is the ER environment conducive to these diverse functions and how is this unique environment maintained? ER Cytosol pH Lysosomes ~7 0 ~7 0 ~5 0 Calcium Concentration ~7.0 ~7.0 ~5.0 ~0.1 M ~500-1000 M ND Reduction/Oxidation Potential Oxidizing (relative to cytosol) Reducing (relative to ER) ND
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

1/13/2014 8 Why is Ca 2+ concentration high in the ER: Signal Transduction: serves as a reservoir for an important signaling Signal Transduction : serves as a reservoir for an important signaling molecule and maintaining a large gradient allows for rapid signal transmission upon regulated release Molecular Chaperone Activity : many chaperones/foldases are calcium- dependent; e.g. calnexin, calreticulin, BiP/GRP78, among others
Image of page 8
1/13/2014 9 How is a high Ca 2+ concentration maintained in the ER relative to the cytosol? Calcium Concentration ~10 -7 M ~10 -3 M ER Cytosol
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

1/13/2014 10 SERCA structure: 10 TM domains, 3 cytoplasmic domains (A domain: anchor) a P domain (phosphorylation domain) and an N domain (binds ATP). Thapsigargin binds in a cavity S arcoplasmic/E ndoplasmic R eticulum Ca 2+ -ATPase (SERCA): (Inhibited by thapsigargin) near the cytosolic surface near the membrane and inhibits activity Periasamy et al. 2007 Muscle Nerve 35:430
Image of page 10
1/13/2014 11 Sarcoplasmic Reticulum in Muscle Cells Glembotski C C Physiology 2012;27:343-350
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

1/13/2014 12 How is a low Ca 2+ concentration maintained in the cytosol?
Image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern