Renal protein reabsorption is the part of renal physiology

Renal physiology

Renal physiology is the study of the physiology of the kidney. This encompasses all functions of the kidney, including reabsorption of glucose, amino acids, and other small molecules; regulation of sodium, potassium, and other electrolytes; regulation of fluid balance and blood pressure;...

 that deals with the retrieval of filtered protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s, preventing them from disappearing from the body through the urine.

Almost all reabsorption takes place in the proximal tubule

Proximal tubule

The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman's capsule to the loop of Henle.-Structure and appearance:...

. Only ~1% is left in the final urine.

The proteins cross the apical membrane by endocytosis

Endocytosis

Endocytosis is a process by which cells absorb molecules by engulfing them. It is used by all cells of the body because most substances important to them are large polar molecules that cannot pass through the hydrophobic plasma or cell membrane...

. They are subsequently degraded in lysosome

Lysosome

thumb|350px|Schematic of typical animal cell, showing subcellular components. [[Organelle]]s: [[nucleoli]] [[cell nucleus|nucleus]] [[ribosomes]] [[vesicle |vesicle]] rough [[endoplasmic reticulum]]...

s. The remaining free amino acids are transported across the basolateral membrane by amino acid transporter

Amino acid transporter

An amino acid transporter is a membrane transport protein that transports amino acids. They are mainly of the solute carrier family.-Solute carrier family examples:* high affinity glutamate and neutral amino acid transporter...

s.

Overview table

Characteristics of oligopeptide reabsorption

Characteristic	proximal tubule Proximal tubule The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman's capsule to the loop of Henle.-Structure and appearance:...			loop of Henle Loop of Henle In the kidney, the loop of Henle is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its discoverer F. G. J...	Distal convoluted tubule Distal convoluted tubule The distal convoluted tubule is a portion of kidney nephron between the loop of Henle and the collecting duct system.- Physiology :It is partly responsible for the regulation of potassium, sodium, calcium, and pH...	Collecting duct system Collecting duct system The collecting duct system of the kidney consists of a series of tubules and ducts that connect the nephrons to the ureter. It participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and antidiuretic hormone.There are several...
	S1	S2	S3
reabsorption (%)	99
reabsorption (mmoles Mole (unit) The mole is a unit of measurement used in chemistry to express amounts of a chemical substance, defined as an amount of a substance that contains as many elementary entities as there are atoms in 12 grams of pure carbon-12 , the isotope of carbon with atomic weight 12. This corresponds to a value... /day)
Concentration
apical transport	endocytosis Endocytosis Endocytosis is a process by which cells absorb molecules by engulfing them. It is used by all cells of the body because most substances important to them are large polar molecules that cannot pass through the hydrophobic plasma or cell membrane...
basolateral  transport proteins	amino acid transporter Amino acid transporter An amino acid transporter is a membrane transport protein that transports amino acids. They are mainly of the solute carrier family.-Solute carrier family examples:* high affinity glutamate and neutral amino acid transporter...
Other reabsorption features