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1. G - PROTEINS
Student Name - 1. Vaishnavi Sanjay Bagade
2. Tejas Wani
Student Coordinator – GELASHVILI MARIAMI

2. alpha
beta
Gamma

4. WE WILL BE SEEING --
• Definition
• Structure
• Function
• Clinical Correlations
• Pathophysiology
• Causes
• Diagnosis
• Treatment

5. DEFINITION
• G proteins, also known as guanine
nucleotide-binding proteins
• They are a family of proteins that
act as molecular switches inside
cells, and are involved in
transmitting signals from a variety of
stimuli outside a cell to its interior.

6. STRUCTURE
• The G-protein is
heterotrimeric
• Also called "large" G
proteins.

7. FUNCTION
• G proteins are important in transmitting signals from
hormone receptors, sensory neurons, and other
modulatory molecules to the cell machinery.
• They function as a switch, being turned on and off by
signal-receptor interactions on the cell surface

8. ALPHA G- PROTEIN
• G alpha subunits are one of the
three types of subunit of
guanine nucleotide binding
proteins, which are membrane-
associated.

9. CLINICAL CORRELATIONS
•1. sporadic endocrine tumors
•2. McCune-Albright syndrome
•3. hereditary osteodystrophy

10. 1. SPORADIC ENDOCRINE TUMORS
• These are neoplasms that arise from cells of the endocrine
(hormonal) and nervous systems.
• They most commonly occur in the intestine, where they are often
called carcinoid tumors, but they are also found in the pancreas,
lung, and the rest of the body.

11. SIGNS AND SYMPTOMS
• diarrhea
• asthma or wheezing
• congestive heart failure (CHF)
• abdominal cramping
• peripheral edema
• heart palpitations

12. PATHOPHYSIOLOGY
• These are believed to arise from various neuroendocrine
cells whose normal function is to serve at the
neuroendocrine interface. Neuroendocrine cells are
present not only in endocrine glands throughout the
body that produce hormones, but are found in all body
tissues

13. DIAGNOSIS
• Markers
• Imaging
• most important markers are:
• chromogranin A
• urine 5-hydroxyindoleacetic acid
• neuron-specific enolase
• synaptophysin

14. TREATMENT
• Surgery
• Symptomatic relief
• In secretory tumors, somatostatin analogs given subcutaneously
or intramuscularly alleviate symptoms by blocking hormone.
• Chemotherapy
• Radionuclide therapy

15. MCCUNE-ALBRIGHT SYNDROME
• McCune–Albright syndrome is a complex genetic disorder affecting-
the bone
skin
endocrine systems.
It is a mosaic disease

17. SIGNS AND SYMPTOMS
• Fibrous dysplasia .
• Hyperpigmented skin lesions with characteristic features,
including jagged "coast of Maine" borders
• Hyperfunctioning endocrine disease.
• Precocious puberty: The most common endocrinopathy is
precocious puberty, which presents in girls (~85%)

18. DIAGNOSIS
• McCune–Albright syndrome has different levels of severity.
• For example, one child with McCune–Albright syndrome may be
entirely healthy, with no outward evidence of bone or endocrine
problems, enter puberty at close to the normal age, and have no
unusual skin pigmentation. Diagnosis may be made only after
decade.

19. TREATMENT
• For treatment of precocious puberty, the aromatase inhibitor
such as letrozole is effective.
• Hyperthyroidism is managed with medications such as
thioamides
• Oral phosphate and calcitriol may be given for treatment of
hypophosphatemia
• Surgical management of skeletal abnormalities

20. HEREDITARY OSTEODYSTROPHY
• Pseudohypoparathyroidism
• It is a condition associated primarily with resistance to the parathyroid
hormone.
• Those with the condition have a low serum calcium and high phosphate, but
the parathyroid hormone level (PTH) is inappropriately high

21. PRESENTATION
• Patients may present with features of hypocalcaemia
including carpo-pedal muscular spasms, cramping,
tetany, and if the calcium deficit is severe, generalized
seizures

23. DIAGNOSIS
•hypocalcemia
•hyperphosphatemia
•elevated parathyroid hormone
(hyperparathyroidism)
•Suppressed calcitriol levels

24. TREATMENT
• Calcium and Calcitriol supplements, the latter with a
larger dose than for treatment of hypoparathyroidism.
• Treatment consists of maintaining normal levels of
calcium, phosphorus, and vitamin D. Phosphate
binders, supplementary calcium and vitamin D will be
used as required