Annotation Conf. Call 2016-10-25
Bluejeans URL: https://bluejeans.com/993661940
Agenda
Meetings
Next GOC Meeting - USC, Los Angeles, CA, November 4-6, 2016
- Link to a registration form is now available for the USC Meeting on the Meeting Logistics Page.
- Register for meeting and dinner, just dinner, just meeting.
- No registration fee for the Noctua workshop.
- Draft Agenda - please review
Discussion of Outstanding github Tickets
- NTR: maintenance of differentiated cell state
- Paper: miR-1, miR-10b, miR-155, and miR-191 are novel regulators of BDNF.
- accompanying LEGO model
Annotation Consistency Exercise
Abstract AIM:To elucidate the sequential transfer of iron amongst ferritin, transferrin and transferrin receptor under various iron status conditions.
METHODS:Incorporation of 59Fe into mucosal and luminal proteins was carried out in control WKY rats. The sequential transfer of iron amongst ferritin, transferrin and transferrin receptor was carried out in iron deficient, control and iron overloaded rats. The duodenal proteins were subjected to immunoprecipitation and quantitation by specific ELISA and in situ localization by microautoradiography and immunohistochemistry in tandem duodenal sections. Human duodenal biopsy (n = 36) collected from subjects with differing iron status were also stained for these proteins.
RESULTS:Ferritin was identified as the major protein that incorporated iron in a time-dependent manner in the duodenal mucosa. The concentration of mucosal ferritin was significantly higher in the iron excess group compared to control, iron deficient groups (731.5 +/- 191.96 vs 308.3 +/- 123.36, 731.5 +/- 191.96 vs 256.0 +/- 1.19, P < 0.005), while that of luminal transferrin which was significantly higher than the mucosal did not differ among the groups (10.9 +/- 7.6 vs 0.87 +/- 0.79, 11.1 +/- 10.3 vs 0.80 +/- 1.20, 6.8 +/- 4.7 vs 0.61 +/- 0.63, P < 0.001). In situ grading of proteins and iron, and their superimposition, suggested the occurrence of a sequential transfer of iron. This was demonstrated to occur through the initial binding of iron to luminal transferrin then to absorptive cell surface transferrin receptors. The staining intensity of these proteins varied according to the iron nutrition in humans, with intense staining of transferrin receptor observed in iron deficient subjects.
CONCLUSION:It is concluded that the intestine takes up iron through a sequential transfer involving interaction of luminal transferrin, transferrin-transferrin receptor and ferritin.
Discussion Points
- What can be done with ferritin annotations, since a specific subunit was non identified in the paper?
- Should colocalization (IEP) data be used for biological process annotations?
- If an iron transport annotation is made, does an iron homeostasis annotation impart any additional information?
- Is "intestinal absorption" too broad? Should an intestinal iron absorption term be requested?
Accompanying LEGO Model
Annotations
Gene Symbol, Gene Name | GO term/ID | Evidence Code | Annotation Source | Annotation Extension | Comment |
---|---|---|---|---|---|
Biological Process | |||||
ferritin | iron ion transport GO:0006826 | IDA | FB, Tair | Which ferritin subunit? | |
Tf, transferrin | iron ion transport GO:0006826 | IDA | FB, Tair | transport is inferred from radioactive Fe sequential colocalizing with location of each of the proteins in different parts of the duodenum | |
Tfrc, transferrin receptor | iron ion transport GO:0006826 | IDA | FB, Tair | Tfrc or Tfr2? | |
Tf, transferrin | ferric iron transport GO:0015682 | IDA | RGD | ||
ferritin | ferric ion import GO:0033216 | IDA | SGD | occurs_in UBERON:0000320 duodenal mucosa | |
Tf, transferrin | ferric ion import GO:0033216 | IDA | SGD | occurs_in UBERON:0000320 duodenal mucosa | |
Tf, transferrin | GO:0098706 -ferric iron import across plasma membrane | IEP | WB | ||
Tfrc, transferrin receptor | GO:0098706 -ferric iron import across plasma membrane | IEP | WB | ||
ferritin | iron ion homeostasis GO:0055072 | IDA | FB | Which ferritin subunit? | |
Tf, transferrin | iron ion homeostasis GO:0055072 | IDA | FB | transport is inferred from radioactive Fe sequential colocalizing with location of each of the proteins in different parts of the duodenum | |
Tfrc, transferrin receptor | iron ion homeostasis GO:0055072 | IDA | FB | ||
ferritin, Fth1, Ftl1 | GO:0060586 - multicellular organismal iron ion homeostasis | IEP | WB | occurs_in(UBERON:0016512) lumen of duodenum | |
Tf, transferrin | GO:0060586 - multicellular organismal iron ion homeostasis | IEP | WB | occurs_in(UBERON:0016512)lumen of duodenum | |
Tfrc, transferrin receptor | GO:0060586 - multicellular organismal iron ion homeostasis | IEP | WB | occurs_in(UBERON:0002114) duodenum | |
Tf, transferrin | GO:0050892 - intestinal absorption | IEP | WB | has_input(ChEBI:29034) | Maybe request "intestinal iron ion absorption". |
Tfrc, transferrin receptor | GO:0050892 - intestinal absorption | IEP | WB | has_input(ChEBI:29034) | |
Tf, transferrin | response to iron ion GO:0010039 | IEP | RGD | movement between compartments dependent on iron level in diet | |
Tfrc, transferrin receptor | response to iron ion GO:0010039 | IEP | RGD | ||
human ferritin, FTH1 (UniProtKB:P02794), FTL (UniProtKB:P02792) | GO:0060586 - multicellular organismal iron ion homeostasis | IEP | WB | occurs_in(UBERON:0002114) duodenum | |
human TF (UniProtKB:P02787) | GO:0060586 - multicellular organismal iron ion homeostasis | IEP | WB | occurs_in(UBERON:0002114) duodenum | |
human TFRC (UniProtKB:P02786) | GO:0060586 - multicellular organismal iron ion homeostasis | IEP | WB | occurs_in(UBERON:0002114) duodenum | |
Cellular Component | |||||
Tf, transferrin | cell tip GO:0051286 | IDA | RGD | Figure 5 - ID, 15 min; text description | |
Tfrc, transferrin receptor | cell surface GO:0009986 | IDA | RGD | Figure 5; text description | |
Tfrc, transferrin receptor | GO:0031528 - microvillus membrane | IDA | WB | ||
Tf, transferrin, Fth1, Ftl1, ferritin | GO:0005615 - extracellular space | IDA | WB | ||
Molecular Function | |||||
Fth1, Ftl1, ferritin | iron ion binding, GO:0005506 | IDA | FB, Tair, WB | occurs_in UBERON:0000320 duodenal mucosa | Which ferritin subunit? |
Tf, transferrin | iron ion binding, GO:0005506 | IDA | FB, Tair, WB | occurs_in UBERON:0000320 duodenal mucosa | |
Tf, transferrin | ferric iron binding GO:0008199 | IDA | RGD, SGD | ||
ferritin | ferric iron binding GO:0008199 | IDA | SGD | ||
Tfrc, transferrin receptor | GO:0004998 - transferrin receptor activity | IEP | WB | occurs_in(UBERON:0008346) duodenal epithelium | IEP for MF annotation??? |
Minutes
- On call: Alice, Barbara, Edith, Giulia, Helen, Kimberly, Li, Midori, Olivia, Paola, Paul T., Penelope, Petra, Sabrina, Sage, Stacia, Stan, Tanya, Val
Next GOC Meeting - USC, Los Angeles, CA, November 4-6, 2016
- Please register if you haven't already
- Please check the meeting agenda to see what topics will be discussed
- If you are interested in raising a topic for discussion, please add it along with your name and the amount of time you think will be needed
Annotation Consistency Exercise
- Issues we discussed:
- Determining what annotations could be made to ferritin
- Authors used an antibody, but didn't say exactly what the antibody recognized and there are many different potential subunits to the rat ferritin complex (light and heavy chains)
- Differences in evidence code usage
- Most curators used IDA for the transport annotations, but there was also IEP
- There was some discussion about use of IC to support annotations, as there didn't seem to be a single experiment that showed both iron binding and transport
- Support for iron homeostasis annotations?
- We discussed whether an iron homeostasis annotation added much if the proteins were already annotated to irton transport
- Did the experiments simply show support for nutrient uptake or was there also support for homeostasis?
- Annotations to intestinal absorption
- Seems a broad, high level term to use, but could be made more specific with annotation extensions, e.g. has_input(ferric ion), or by requesting a new, more granular term like intestinal iron absoption.
- For terms like intestinal iron absorption, the potential list of terms could get very long - is this necessary? Would an alternative term such as intestinal metal ion absorption be a reasonable alternative?
- Additional papers with knock-down experiments might help to better support the Biological Process annotations
- Cellular component annotations
- What evidence is sufficient to annotate to cell surface vs a membrane term? Note that this issue has been raised before and will be discussed at the GOC meeting next month.
- Molecular function annotations
- What evidence would support the transferrin receptor activity annotation? Maybe IC, but not IEP.
- Determining what annotations could be made to ferritin
- Review of Noctua model:
- Ferritin is represented in this model by the generic GO complex, so no specific annotations to a rat complex, or particular subunits, would be made
- The model represents the relation between transferrin and the transferrin receptor as 'directly provides input for'
- David was not certain that this was the best relation to use, but wanted to capture the idea that there was some sort of causal relation between the transferrin and the transferrin receptor that led to uptake into the epithelium
- Note that it would be fine to use evidence from more than one paper to support a given LEGO model